Well, I am a bit of a noob, and people are probably going to shrug this off, but here is my best shot.
Top Tier:
~ Snake - Has won the most tournaments. Intense mind games, easily the best atm.
~ Meta Knight - Racks up damage quick and can kill easily too.
~ Game & Watch - Good at just about everything, bucket is great. Buffed the most from melee.
High Tier:
~ Olimar - Only thing lacking his is recovery. Also check
this out.
~ King DeDeDe - Side B is great, can chaingrab, great recovery, and isn't all slow.
~ Marth - Great spacing game with good range and a very powerful tip. Broken Fair.
~ Wolf - Forward smash is one of the best, spammable laser and a reflector.
~ Falco - Very spammable SHDL, amazing air game and not a bad ground game.
~ Toon Link - Very similar to Falco, his Bair is great.
~ Wario - Amazing air game, good ground game, great recovery and fart.
~ Pit - Gay arrows and side B.
~ Diddy Kong - Great air game, and bananas.
~ Kirby - The first big suprise on my tier list, Kirby honestly could be even higher. Amazing aerials, can gimp very easily, combos out of grabs, very good at racking up damage and KO'ing and intense recovery. Only downside I can think of is light weight.
Middle Tier:
~ Pokemon Trainer - The other big suprise on my tier list, usually at the top of low, but should be way higher. Has almost no bad matchups, is heavy, light and middle, plus all three of the pokemon could be effective on their own.
~ Pikachu - A good Pikachu is one of the most annoying things out there. QAC is great.
~ Zelda - Din's fire plus amazing tilts and smashes, can get juggled easily though.
~ ROB - Combos and projectiles.
~ Ice Climbers - Can pretty much not be grabbed, and can do amazing things with the grab, plus attacks that deal huge damage. coughdsmashcough
~ Luigi - Great air game. Good recovery. Good character. Could rise.
~ Ness - OMG higher than Lucas what a noob. Seriously though, tell me one thing that Lucas has over Ness.
~ Charizard - Best of the PT pokemon IMO because it is a tank. Rock Smash is beastly, so is flamethrower and has huge killing potential.
~ ZSS - Good but hard to get that kill.
~ Donkey Kong - Amazing Bair, his big frame can be abused though.
~ Lucas - Worse ness
~ Fox - Nerfed a ton
~ Ivysaur - Bullet seed is arguable the best move in the game, a great projectile and very easy to kill with. Probably should be higher, but the recovery is arguable the worst.
~ Shiek - My main in melee, but is nerfed now.
~ Ike - Can be a beast if used correctly, but is so punishable.
~ Squirtle - Great air game but dies a lot and is fairly hard to kill with.
Low Tier:
~ Peach - This was a bit of a guess actually.
~ Sonic - Can not sweetspot the edge, aerials lack priority but is fairly fast.
~ Mario - In a game where average isnt good enough.
~ Bowser - Buffed a fair bit, actually usable.
~ Ganondorf - Can tech chase but is very slow.
Bottom Tier:
~ Link - Toon Link overshadows it and uhh i dunno.
~ Yoshi - Not very good.
~ Captain Falcon - Bleh