Endlessages - MMOFPSRPG Made by a very small indy style dev team very awesome game tho played for 10 years easily.
SWG - Not very long but fell in love very amazing game.
STO - Big SciFi fan and love Star Trek but the over carebearization ruined this game for me but played from Beta till about a year ago.
EvE - 2 years, however, due to RL I never found time to play. PvPers paradise if you can spend 24/7 playing it to get any where.
WoW - Probably going on 4 years now. Only for PvP I can't stand PvE content in that game.
Had a lot of bad experiences with BS single player style games so I never bothered checking out any other TES games, but I got into Skyrim, and needless to say feel in love. The prospect of an online version of that amazing universe was the most exciting game related news I have heard in many years.