In my opinion, Ice Climbers should be first, Meta Knight second, Diddy Kong third, Olimar fourth and Snake fifth.
Why? Well, Ice Climbers are by far (In my opinion) the best character in the game. If you dominate the defensive game, and chaingrabs, there shouldn't be a reason to even lose. Especially since most people want to use the Japanese ruleset, where there is no place to CP ICs, and also, people wanting to ban MK, arguably, the best char vs Ics (Again, in my opinion). How would ICs lose then? We all know what they're capable of, it's just that dominating them is the hard thing. Not using them.
Meta Knight... well, Meta Knight! If he isn't first, he's obviously second.
Diddy Kong: Basically, he has so much good things in his overall gameplay, that I consider him to be better than Olimar and Snake. Strong aerial and ground game. Can get out out juggles, decent recovery, IMO, best kill "setups" in the game, excellent defensive and aggressive game. He can do pretty much anything, from my perspective. Why he isn't 2nd or 1st? Even with infinites? Because they can be SDI'ied, and when we have a chance to escape them, it's not the best anymore. Also add the dificulty to set them up and do them. Also, MK is MK, and Ice Climbers grab are better than any other infinite. The meaning of 1 grab = Death, is just way too much. One simple read.
Olimar is an extremely good character. Where from my perspective, his only weakness is his short recovery. Excellent move set, aerial game (Whistle, and aerials) and ground game. He has such a strong defensive game, where he simply overwhelms characters AND players. Also, his grab range pretty much destroys certain matchups, where they just can't... simply attack without being punished. Add this to the excellent Olimars players we have, where they have always shown how good their character really is and what he can do.
Snake is simply the best character after Olimar. Simple as that. We all know what Snake is capable of, and how good of a character he is.