The original Metal Gear Solid wins it for me in almost every category possible. The gameplay I felt was the best for it's time. It didn't feel dated in 1998, but actually felt refreshing and new. Every MGS after that has given me the feeling that they could have learned a little more from other games to get up to par, especially MGS3. MGS4 comes in second in that regard for being totally inspired by Resident Evil 4 and getting a workable control scheme because of it. The story in MGS was the best also and has basically in one form or another been duplicated in each sequel since, except for MGS3. MGS4 is horribly guilty of borrowing far too much from the original, right down to the villains lifted directly from the first, except without the heart behind them. I always felt the original's strength lied in it's killer rogue's gallery of villains and their amazing personalities. I never got that feeling again about the entirety of the villains in any of the other games. MGS4 would be the most guilty of this since you don't know jackshit about any of the Beauties until you defeat them.
Overall:
1. MGS
2. MGS 4
3. MGS 3
4. MGS 2
5. MGS: PO
Tag: Became a freaking mod and a complete douche, coincidentally, at the same time.
