From best to worst
GT5 Definitely, my most played game this gen. I hope they'll start releasing more tracks regularly. Spa was on the top of my list of tracks I wanted and next week it's here :)
MGS4 Great experience, awesome sound design. Tons of memorable moments.
FF13 Looked great, at least the graphics delivered, but it took forever to get going. Gran Pulse saved the game, a welcome break in the long corridors. Still good, but a step back from FF12.
GTA4 Started out great, then it became more and more annoying. I finished the story with cheats, the clunky controls and ridiculous waves of bad guys were too much for me. Driving around the city was fun, same as flying around but in the end it was a big step back from the game play variety San Andreas offered. (Although controls were terrible in San Andreas too, I didn't even manage to finish the third city with cheats)
I haven't played Halo3.