Sacred, anyone remember that? The lil Diablo 2 Clone? Played it through, on silver mode after i bought it in 1 1/2 Day, only taking breaks to go to the bathroom and get something to drink..well and eat when i really had to, used to eat while playing though. When i was done my whole right arm had cramped up, could barely move it cause it was in one position for a long time, only moving the mouse.
Longest though, well Diablo 2 i guess, played it for 2-3 Years before finally quitting, though i never played it really intensive like constantly several hours at a time, just the usual few runs and such, back when it was still good in 1.09 ;p
Played WoW too, used to play every damn day the week, for hours, though since there wasnt enough content for me (no only items are NOT content worth paying for or investing that much time) i quit twice, once after 1 Month and the second time after 5, never got back to it and probably never will.
Mass Effect got me hooked right now, as does Darkstar One and as soon as they come out, either Diablo 3 (its been announced!), Jumpgate Evolution, Darkfall, Black Prophecy, Stargate Worlds and Fable 2 (which im actually looking forward to)..dont think any other game could make me play alot again, nor are there any other good games announced right now i'd consider.