Grand Theft Auto. That's the official answer. Tony Hawk and Need For Speed are almost as good. There's also this new game for PS2 coming out soon that looked good, forgot what it was called.
South Park, Charmed, Buffy The Vampire Slayer / Angel, Tru Calling, Family Guy, TrippingTheRift, FreeForAll, Futurama, Jackass, Lost, That 70's Show, Celebrity Deathmatch