Ah hell I can't pick between those!
It's a toss up between; San Andreas, Vice City, FFX, FFXII, Sands of Time, Burnout 3 and Burnout: Takedown.
Not on that list (off the top of my head) I would probably add a Crash Bandicoot game on there, and a Spyro the Dragon game too. Was Just Cause on the PS2? I'll add that. As well as some FIFA games too, maybe 2005? God there were so many good games but I can't remember most of them!
I guess maybe Vice City because I think I spent the most time (barring the grinding in FF) playing that.