metal gear solid 4 was the greatest game to hit the ps3 at the time. no questions asked. i even bought the 80gb bundle when it came out just to give sony and hideo kojima extra support. i couldnt believe my eyes when i saw this game. the graphics were absolutely amazing, and i loved the nod it gave to earlier mgs games. a real treat for gamers.
Metal Gear Solid 3 >>>> Metal Gear Solid 2 >>>>> Metal Gear Solid 1 >>>>>>>>>>> Metal Gear Solid 4
(note i like all of them but 4 has some serious problems in my eyes that i just can't look past)