What is the most addictive game that you have ever played?

[Jereel Hunter]

1) (tie) EverQuest and StarCraft
3) Halo 1/2 were addictive to me. Nowhere near the extent to which the first two were though. I would play Halo 1 multiplayer on every possible occasion.. Halo 2 as well. (Also, trying to beat Halo 2 on legendary became an obsession for me for a while)