I decided I'd like to revitalize this thread a little :)
Here is my holy trinity of Affinity:
Steelblade
// Lands (16)
4 [UNH] Plains
4 [MR] Ancient Den
4 [DS] Darksteel Citadel
4 [DS] Blinkmoth Nexus
// Creatures (20)
4 [R] Ornithopter
4 [NPH] Vault Skirge
4 [UL] Mother of Runes
4 [WWK] Stoneforge Mystic
4 [NPH] Puresteel Paladin
// Spells (24)
4 [MBS] Flayer Husk
1 [NPH] Batterskull
4 [FD] Cranial Plating
1 [BOK] Umezawa's Jitte
1 [DS] Sword of Fire and Ice
1 [MBS] Sword of Feast and Famine
1 [DS] Sword of Light and Shadow
4 [FD] Paradise Mantle
3 [SOM] Mox Opal
4 [NPH] Dispatch
// Sideboard (15)
SB: 1 [SOK] Manriki-Gusari
SB: 1 [M12] Swiftfoot Boots
SB: 1 [MBS] Mortarpod
SB: 4 [LRW] Oblivion Ring
SB: 2 [ALA] Ethersworn Canonist
SB: 2 [MBS] Phyrexian Revoker
SB: 2 [DKA] Grafdigger's Cage
SB: 2 [DK] Tormod's Crypt
This version plays like a white weenie deck, with a twist. You play the typical white weenie game with creatures like Mother of Runes and Stoneforge Mystic with equipments, but you combine it with the explosiveness of affinity. The deck is built around Puresteel Paladin, who gives the deck a massive card advantage engine and makes all the equipment costs free. Flayer Husk is this decks Arcbound Worker, and the deck has tons of artifacts to enable Metalcraft and Cranial Plating.
Metalboros
// Lands (16)
4 [ON] Flooded Strand
3 [R] Plateau
1 [UNH] Plains
4 [MR] Ancient Den
4 [MR] Great Furnace
// Creatures (24)
4 [SOM] Memnite
4 [MR] Frogmite
4 [CFX] Court Homunculus
4 [MBS] Ardent Recruit
4 [SOM] Auriok Sunchaser
4 [NPH] Porcelain Legionnaire
// Spells (20)
4 [R] Lightning Bolt
4 [SOM] Galvanic Blast
4 [NPH] Dispatch
4 [FD] Cranial Plating
4 [SOM] Mox Opal
// Sideboard (15)
SB: 3 [MBS] Phyrexian Revoker
SB: 3 [DKA] Thalia, Guardian of Thraben
SB: 3 [LRW] Oblivion Ring
SB: 3 [SC] Sulfuric Vortex
SB: 3 [DK] Tormod's Crypt
This version plays like a Zoo deck, with a twist. You're structured fairly similar to Zoo, with the appropriate curve of 1-drops, 2-drops, and 12 1cc spot removal spells, but the deck is capable of exploding with Mox Opal and Cranial Plating. The spot removal clears the way for the groundbound guys to push damage through, and the Sunchasers and Legionnaires are great Plating-wearers. Blast and Dispatch are much stronger than Chain and Path.
Esper Tezzerator
// Lands (17)
4 [MR] Seat of the Synod
4 [MR] Vault of Whispers
4 [MR] Ancient Den
4 [R] Underground Sea
1 [US] Gaea's Cradle
// Creatures (20)
4 [VI] Phyrexian Walker
4 [R] Ornithopter
4 [GTW] Vault Skirge
4 [PC2] Baleful Strix
4 [WWK] Stoneforge Mystic
// Spells (23)
4 [MR] Thoughtcast
3 [MBS] Tezzeret, Agent of Bolas
4 [ARB] Thopter Foundry
1 [FUT] Sword of the Meek
4 [FD] Cranial Plating
3 [LRW] Springleaf Drum
4 [SOM] Mox Opal
// Sideboard (15)
SB: 4 [JU] Cabal Therapy
SB: 3 [LRW] Oblivion Ring
SB: 2 [SOK] Pithing Needle
SB: 2 [BOK] Umezawa's Jitte
SB: 2 [ALA] Relic of Progenitus
SB: 2 [SOM] Nihil Spellbomb
This version plays like the more traditional combo affinity lists, with a twist. Thopter Foundy gives this deck serious resilience to removal, both single target and mass effect. The insane amount of card advantage allow this deck to consistently find its combo pieces. The card advantage and Thopters give this deck an incredible amount of resiliency overall. This version is more of a combo/control version than an aggro version, but still uses Plating as its primary means of victory. Walker is used over Memnite because it holds back aggro against opposing creatures in the early game while it sets up its card advantage and combo pieces, but it can still attack with a Plating unlike Shield Sphere, and Thopter can turn it into a 1/1 flier later on.
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If anyone would like a more detailed write-up on any of the lists, thorough card explanations, etc... let me know. These lists have been pretty thoroughly tested and optimized; they're not just some randomly thrown together piles that I thought would look cool.

