Muktol

Some tipps and suggestions, based on my monoW equipment deck (http://www.mtgvault.com/muktol/decks/monow-kor-equipment/)
As you have a rather low mana-curve, you could try to reduce the number of land by 1-3.
I would definitly reduce the number of creatures and add some more to ensure you have enough of them to equip the creatures you have on the battlefield.

Suggestions:
Auriok Glaivemaster ({W}; 1/1; As long as Auriok Glaivemaster is equipped, it gets +1/+1 and has first strike), Etched Champion ({3}; 2/2; Metalcraft -- Etched Champion has protection from all colors as long as you control three or more artifacts), Goblin Gaveleer ({R}; 1/1; trample; Goblin Gaveleer gets +2/+0 for each Equipment attached to it)
Basilisk Collar ({1}; {2} to equip; creature gets deathtouch and lifelink), Bone Saw ({0}; {1} to equip; creature gets +1/+0), Bonesplitter ({1}; {1} to equip, creature gets +2/+0), Cranial Plating ({2}; {1} to equip; creature gets +1/+0 for each artifact you control) Swiftfoot Boots ({2}; {1} to equip; creature gets hexproof and haste)

Greetings
Muktol

Depends on how you want to play this. Vampire decks normaly try to be fast as hell (I have seen a single deck that was built for midgame-tactics) and if you wnt to do so, you can remove some spells.
Second question would be the legality. As you didn't tag any legality I assume that you want to play either kitchen table (where legality is no big mather) or modern.

Greetings
Muktol

Some alternatives:
"Liliana's Caress" against "Megrim"...cheaper to play and the life-loss can't be prevented
"The Rack" against "Shrieking Affliction"...The Rack activates it's ability a little easier and perhaps more often
"Smallpox" against "Mental Agony"...Smallpox attacks all recourses you and your opponent have: mana, life, cards and creatures. The only thing of these which might hurt you a little bit is the own discard. If you don't want to use Smallpox, I would nevertheless remove Mental Agony, as it is rather expensive to play, and maximize some other slots .

"Scepter of Fugue" could be an interesting Artifact for you, as it enables you to remove a handcard from your opponent every turn, no matter what cards you have on your hand.

Greetings
Muktol

Where's the fun on winning all the time without any effort ;)

On the one hand, the Gatekeeper is hard to support (especially with your manabase) as in 99% of the times you want to cast him he needs triple {B}.
On the other hand he benefits from beeing a vampire ("Stromkirk Captain" and "Vampire Nocturnus") and can even remove rexproof or indestructible creatures (when they are alone on the field, otherwise it's your opponents choice)
"Ash Zealot" is a human and doesn't benefit from the vampire buffs. He also works only if someone casts anything from the graveyard (flashback, unearth, and so on) so if this happens rather often in your matches he is at last work sideboarding, if not, stay with the Gatekeeper. If you want to replace him with an aggro creature, I would tend to use "Bloodghast"

I know the drawback on life isn't that big in this deck but it's one of the few creatures I don't like here. You could perhaps take a look at "Bloodghast" (can't block, comes again from grave with landfall)
If you want to dig a little deeper with carddraw, try "Read the Bones" ({2}{1}, pay 2 life; scry 2 then draw 2 cards) instead of "Sign in Blood"

Mouth (/ fingers) faster than Brain -> If I get the chance to do some testgames, I will give 1-2 Purphoros, "God of the Forge" and 2-3 "Nykthos, Shrine to Nyx" a try.

A very simple (and silly) one: I don't have any free slots, and I don't know what I could remove to make some space for it ;)
As for "Nykthos, Shrine to Nyx", I think I won't need ramp in any form. The mana-costs are very low ("Siege-Gang Commander" is not supposed to be hardcast but brought into play with "Warren Instaigator") and even if it doesn't look like that, I work a great deal with tokens here (My opponents tend to shoot many goblins down, dont know why *g*) and those don't count towards devotion (cc0). I also don't have any 'pay X, deal X damage' spells in here.
"Purphoros, God of the Forge" is a nice card, could also give me another winoption, but it has the same mana-costs as Krenko, and furthermore, does nothing if he is alone on the field. I could try to replace "Furystroke Giant" with it, but that would require some test-games, I don't have the time for at the moment :(

I use defender-ramp in my G/W angel deck (http://www.mtgvault.com/muktol/decks/wg-tribal-angel/)
"Axebane Guardian", "Overgrown Battlement" provide mana and "Perimeter Captain" helps to stay alive against aggro.

If you want to add this 'engine' I would do the following changes:
-2 Cultivate
-2 Rampant Growth
-2 Scouting Trek
-3 Knight of the White Orchid
-3 Gatecreeper Vine (You don't use any gates, and there are better defenders)
-2 Seraph of Dawn
Sideboard 3 "Solemn Offering"
= -17

+4 Axebane Guardian
+4 Order of the Stars (Or any other good cc1 defender)
+4 Overgrown Battlement
+4 Perimeter Captain
=+16

With the free slots I would fill up either "Ajani's Pridemate" or some other spells you use.
Furthermore, I would change to some duallands and, if the defender ramp works, you could try to reduce the number of lands to 20.

Greetings
Muktol

*like*
In my B/W pauper vampire deck (http://www.mtgvault.com/muktol/decks/bw-paupervampire-sacrificing/) I use humans to buff up "Falkenrath Torturer". For me "Driver of the Dead" has shown it's value there, as he can bring creatures back from the grave to the battlefield (and not like "Disentomb" only onto your hand) and then can also be sacrificed.
Personaly I like to place +1/+1 counters rather than buff the creature up, so I use "Bloodflow Connoisseur" as second sac-outlet. I think that this might also work for your plan, as it looks to me that you want to stay defensive and defeat your opponents with "Blood Artist" / "Kalastria Highborn". Thus "Vampire Lacerator" also could be replaced with e.g. "Butcher Ghoul"; cc2 vs cc1, I know, but the undying could serve you well.

At last, I would take a look at cheap hexproofe equipments, to give your key-creatures some protection, e.g. "Swiftfoot Boots"

I hope I was able to give you some ideas
Greetings
Muktol

I would try to reduce the number of different creatures but to increase the quantity of the remaining ones. The expensive angels could stay in as 1- or 2-offs, but you will need a good base to defend yourself until you can play them.
My own angel deck is based on G/W and utilizes defender-ramp to get the mana I need (I am able to play any angel I want to with turn 4)

Greetings
Muktol

Some tipps and suggestions, based on my B/R vampire deck (http://www.mtgvault.com/muktol/decks/br-tribal-vampire/)
I would remove "Falkenrath Marauders" and maybe "Gatekeeper of Malakir". The Marauders are a little bit expensive to play without ramp, the Gatekeeper could be a problem to play kicked with his tripple {B}
An alternative to "Rakish Heir" could be "Curse of Stalked Prey", depends if you want to have another blocker, or a harder to remove version of the 'gets a +1/+1 counter' effect.
Furthermore I would increase the number of "Crypt Incursion" but sideboard it. You don't encounter a deck which utilizes the graveyard every day, and the lifegain is useless, as this looks like a aggro deck to me.

Some suggestions:
Blade of the Bloodchief ({1}; {1} to equip; whenever a creature is put into a graveyard from the battlefield, put two +1/+1 counter on equipped vampire)
Bloodghast ({B}{B}; 2/1; can't block; landfall: return from graveyard to play), Bloodline Keeper ({2}{B}{B}; 3/3; flying; further effects see card), Guul Draz Assassin ({1}; 1/1; level up, further effects see card)
Sign in Blood ({B}{B}, pay 2 life; draw two cards), Read the Bones ({2}{B}, pay 2 life; scry 2, then draw 2 cards)
Blackcleave Cliffs (dualland), Graven Cairns (dualland)

I hope I was able to give you some ideas
Greetings
Muktol

I mean no offense, but please read http://www.mtgvault.com/muktol/decks/how-to-build-a-deck/
The short version is, you have far to many different cards in here to give the deck continuity.

Greetings
Muktol

I would remove "Izzet Guildmage", as he is an expensive "Reverberate", and even this spell is heavily discussed in the burn comunity.
Also if you're going for a legacy burn deck there are some other very good burn and ramp spells. I don't know if the storm combo with "Grapeshot" works there, but that could be worth taking a look at.

Greetings
Muktol

I would remove "Battle Hymn" as you don't have any spell which could benefit from a huge amount of mana, and you neither have carddraw to give you enough handcards you could play.
You could either increase the number of "Goblin Chieftain" and "Goblin Wardriver" or change to another card.

Some suggestions, based on my monoR Goblin deck (http://www.mtgvault.com/muktol/decks/monor-tribal-goblins/)
Quest for the Goblin Lord ({R}; enchantment; whenever a Goblin enters the battlefield under your control, you may put a quest counter on Quest for the Goblin Lord. As long as Quest for the Goblin Lord has five or more quest counters on it, creatures you control get +2/+0)
Spikeshot Elder ({R}; 1/1; {1}{R}{R} (no tap!): Spikeshot Elder deals damage equal to its power to target creature or player), Warren Instigator ({R}{R}; 1/1; double strike; whenever Warren Instigator deals damage to an opponent, you may put a Goblin creature card from your hand onto the battlefield), Mogg War Marshal ({1}{R}; 1/1; echo {1}{R}; when Mogg War Marshal comes into play or is put into a graveyard from play, put a 1/1 red Goblin creature token into play); Furystroke Giant ({3}{R}{R}; 3/3; persist; when Furystoke Giant comes into play, other creatures you control gain "{T}: This creature deals 2 damage to target creature or player" until end of turn)
Infiltration Lens ({1};{1} to equip; Whenever equipped creature becomes blocked by a creature, you may draw two cards)

I hope I was able to give you some ideas
Greetings
Muktol

I would reduce the number of different cards a little bit and increase the quantity of the rest. So that you continuous draw the creatures you want to play.

I would add a third "Krenko, Mob Boss" so that you have one on your hand if you need him.
"Skullcrack" belongs into the sideboard, as you don't encounter a lifegain deck every match.

Against the discard of artefact hate you could pack some duallands (3-4) into your sideboard, or some 'pay 1 mana, add 1 mana of any color' lands into your mainboard to use "Ancient Grudge"
No, because the spells converted mana-costs are what counts, and those stay the same, even if you have an effect that says "XYZ spells cost ZYX less to cast"

Goblin Recruiter
Goblin Ringleader
Goblin Wizard
Those would be my choice to remove, but normaly I don't play legacy, and thus don't know much about those cards ;)
My Goblin deck utilizes carddrwa and no tutors to play.

Chalice of the Void: {X}{X} and 1 counter = cc2
Enchantment removal is nearly only white or green. If you manage to stay alive long enough, you don't have to attack: "Goblin War Strike" or "Furystroke Giant" can do the trick without attaking

-1 "Teetering Peaks"
+1 "Mountain"
-2 "Bloodmark Mentor"
+2 "Goblin Bushwhacker"