Best: MGS4
Worst: Metal Gear Ac!d

Best: Metal Gear Solid (PS1)
Worst: Metal Gear Acid (PSP), if your talking about Metal Gear in general :)

3 & 4 are the best. MGS for GBC is the worst (but still really cool).

I'll soon be playing Portable Ops, so things could change.

I found them all amazing and can't pick a winner. But I have a question? Why do so many people dislike mgs2 or think it is the worst. What about it makes it so different from the others? I found it to be quite awesome.

1.MGS4
2.MGS1
3.MGS2
4.MGS3

To me none were bad all were great!!!!

I loved MGS3. All the others are second IMO

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

1.MGS1/3  10/10

2. MGS4    9,5/10  (some answers are... just nonsense, its like "lets say everything is because of the nanomachines, the magic nanomachines that can do anything and answer any question because I really don't know how the hell explain this and that...", and little things like de meryl/johnny scene at the final chapter... awfull scene)

3.MGS2  8   (repetitive. The big shell, go to this room, then that room, the return to the other room... always walking on those bridges just to find an isolated room, once you know how to go to the door, its done, end of the fun in that area. Then you have parts copyed from MGS1, not very imaginative... Things go on, and when you are about to leave it because of the boringness then FLAP! You made your way to arsenal gear, suddenly the game is awesome. then you finish it and everythings ends up being fake and you don't have any clue of what its going on. You have to replay it various times, just to find an even bigger boringness because you already know the way to pass every room and every boss. Then you reach the ending finding new things you ignored, things that turn into more questions. then you quit playing an go live on the forest for some years...)

MGS3 was the best by far.

MGS2 was the worst.

Gameplay: 4 > 2 > 3 > 1
Story: 3 > 1 > 4 > 2
Emotion Factor: 3 > 4 > 2 > 1

Overall: 3 > 4 > 2 > 1