Longtime player:
AC1, UO, AO, SWG (beta), EVE Online (beta), DAOC, AC2, L2 (beta), WOW, M 59:R, Realm (yikes), EQ1, EQ2, Matrix, SOG/DNL, and others...
Greatest Fun I had online - AC1 (2000-2003) greatest game ever. Before the botting and marketplace killed the game.