Chrono Trigger, I did not stop until I had every single ending LOL

Me too! God I didn't know there were any fans of this game here. I feel like I'm the only one commenting on it most of the time.

This gen: Super Smash Bros Brawl.    

Overall, possibly Baldur's Gate series or Super Smash Bros series.  Both clock well into the hundreds of hours.

I'm not sure which individual game I've spent the most time on, but I know that I've spent more time playing the PES franchise than any other...

I'm not 100% sure, but for this generation probably Demon's Souls.  Had to get the platinum.  But Oblivian was definetly right up there.

I'm replaying FF7 now as well, and around 100 hours in.  Want to beat all the weapons...tough work.

Everquest by far. Played that for about 4 years and bought 7 expensions for it. I can't believe it's still going, last year the 17th expansion came out.

At a conservative estimate of 3 hours a day on average that would be well over 4000 hours total. That addiction was expensive back in 2000 on dial up, upto 200 dollar phone bills monthly for the local call to the isp.

counter strike source...
but bad company 1 and 2 had some hours of my life! cant wait for Battlefield 3

Starcraft Brood War

Well, wherever you comment on it, I want to see :). 

super smash bros brawl or nba 2k11 both well over 1000 hours most likely

closest behind that is twilight princess with over 200  same with mass effect 2