Hrm...for the first choice you might as well make it MGS/ Twin Snakes as they're the same only one is a remake.
Well, this is tough. MGS is the one that got me into the series but since MGS2 the game got a complete overhaul with its gameplay mechanics. I'll say that MGS2 has a better story but MGS3 is better overall but only slightly. The environments were a lot more wide and expansive in that one whereas MGS2 felt a bit closed off.
MSG:Twin Snakes was the best. Snake Eater was good, but all the snakes. I hate snakes!!! The only think about MSG2 was when Raiden was butt naked. That was sorta hot. But when the computer said "Havent you played long enough? Turn off the game" I have to admit i was one of the gullable idiots who turned it off. My dad was like, "You are so blonde." LOL!!