I play an all color deck with over 100 cards.
10 of each color land, with a bunch of really powerful creatures that cost a lot to play.
I use a lot of "search your library for x" cards, so i can get those powerful creatures on the field, and i have 4 copies of a card thats like. "1 forest, Tap: Play a creature card from your hand."
Topped off with a bunch of equip cards (Whispersilk cloak+Loxodin Warhammer+ Plated Slagwurm= 11/8 Lifelink, Trample, Unblockable, cannot be target of spells or abilities your opponent controls) and That which was taken, my deck is decent.