1. Assassin's Creed II
PS3 Version - 27 hours or so to complete, everything except feathers and a few of the combat trophies done. Great ending, good setup for a sequel but still good enough to feel like a solid closure to this chapter.
2. God of War
PS3 Version - about 8 hours, I had forgotten that it actually had a decent story. The part were you fight the versions of yourself is still the worst.
3. Uncharted: Drake's Fortune
About 8 hours. Good story, good voice acting, still one of the better looking PS3 games. Final battle was decent, glad there weren't any real boss fights, was a little disappointed with the "monster" type enemies, but at least they were mostly human.
360 Version - no idea how long it took, I'm guessing around 15 hours. I moved slowly and mostly used the enrage and security plasmids for fun. Last boss battle was a little bland, and the ending very short, but the story and setting were great overall.
5. God of War II
PS3 Version - about 11 hours - good game, glad I didn't finish this before because the ending isn't really an ending at all. Boss battles were underwhelming compared to the battles from the first.
6. God of War III
about 9 hours - good game, decent ending, entertaining most of the way through. Could have done without the "forgiveness" portion, or at least have it be shorter and make a little more sense. Graphics were spectacular.
7. Prince of Persia: The Forgotten Sands
PS3 version - Not sure about time, somewhere between 6 and 8 hours probably. Combat was way too easy, puzzles were pretty good, nothing too hard, and the last boss battle, though easy, was excellent.
8. Uncharted 2: Among Thieves
Just shy of 13 hours. Great story and presentation, I would really get into it for a while until another glitch struck and I had to restart from a checkpoint or would die. Took my time with this one looking for treasures.
9. Transformers: War For Cybertron
PS3 version. 8 - 10 hours. Good Transformers story. Level design was a little awkward and repetitive kill box scenarios that eventually wore me down. Last boss was annoying till I figured out driving around in circles would solve all my problems. Overall, an average game based solely on gameplay, but with the story turned out to be pretty decent.
10. Tom Clancy's Splinter Cell: Conviction
360 version. I'm guessing between 9 - 11 hours. Some interesting concepts like the mark and execute feature, and the more casual approach to the stealth side of the game was nice. Overall a good job of making the character feel like a bad ass. Ending was decent. Controls felt a little too floaty, but otherwise a good package.
11. Ratchet & Clank Future: A Crack in Time
Somewhere around 14 hours or so. Collected everything, and beat the extra boss. Good game, not as good as the previous though, I found the story kind of got lost while exploring all the extra planets and things that weren't really story related. Weapons didn't seem as crazy this time and some were just useless. Overall a good game though, the action and platforming are still very good in the series and the graphics are great. Puzzles were pretty good with a few of clanks being fairly challenging.