1. D&D4E
2. D&D3.5 (I love Pathfinder, but it loses out here solely because of the extensive back library for 3.5)
3. Dread (The rules are so simple that I shouldn't even have to take it, but I list it to make sure I get the Jenga tower with it)
4. Star Wars Saga Edition (a generic sci-fi game just doesn't do Star Wars)
5. Savage Worlds (Just edges Alternity and New World of Darkness. Chosen for its versaitility. It does horror, though not as well as Dread, but lets me rolld ice; does modern and sci-fi well; and provides an alternative to D&D for fantasy)
Tougher question than I thought it would be. I love playing so many different games.