Well, I was looking at the deck listings on SCG for the past few Legacy tournies and noticed that the two Vial Affinity decks, which placed 3rd in their tournaments, looked extremely similar, even though the metagames they were in were completely different. As such, I compiled a little list of what cards were in both lists:

4 Aether Vial
1 Ancient Den
4 Arcbound Ravager
4 Arcbound Worker
3 Atog
2 Blinkmoth Nexus
3 Cranial Plating
4 Disciple Of The Vault
3 Fling
4 Frogmite
2 Glimmervoid
4 Great Furnace
2 Ornithopter
4 Seat Of The Synod
4 Terrarion
4 Thoughtcast
4 Vault Of Whispers

3 Engineered Plague
3 Pithing Needle
3 Tormod's Crypt
1 Winter Orb

All together, the only differences are four cards in the main deck and five in the sideboard. Clearly, we're approching some optimal build for Vial Affnity. What I want to ask is, what would you believe that the four missing main deck cards and the five missing sideboard cards should be in a completely unknown metagame?