Fox is supposedly downgraded from his top-tier status in Brawl (Top tier for Melee is Fox/Falco, high tier being Marth, Shiek, and Peach), so I'd be wary of him.
I loathe having to use Captain Falcon, except shen I am screwing around by throwing around Falcon Punches, and hearing him say: "Falcuun... PAWNCH!" or "Show me your moves!"
I like Fox too, the speed is really useful sometimes. But other times, I like a little extra power. Who I choose really depends on how I feel at the moment...
I would be
very careful of listing the best characters in the game. Everybody has some critical disadvantage that is easily exploited by the right matchup. But seriously, Peach as a good character?!? Sure, she can fly, but other than that she sucks!
Definately Capton Falcon. He's fast and hard to knock off the stage.
Also, I like Fox sooooooo much better than Falco. Falco's so freakin slow compared to him, and his b+up and b+side doesn't go as far (don't tell me you tried it and it was the same because I tried it too!). And his pistol doesn't shoot nearly as fast either. Fox just kicks Falco's ***.
Falco's blaster does much more damage and has a knockback effect. Falco's b+up does more damage. Falco doesn't need to go as far with his b+up as he just jumps better. Simple as that.
Marth, Marth, and a side of Marth, please. Marth can quite easily counter any close range attack, and has the best melee range in the game. Unlike Roy, who does more damage the closer his opponent is, Marth does max damage with the tip of his blade. Marth can kill with a smash before his opponent could even touch him.
Marth does, of course, have his weakness. He totally lacks a ranged attack. This becomes a major problem fighting, say, Samus, who has no incentive to allow him to get close. Against that kind of opponent, I'd rather use Falco, but Fox works about as well.
Finally, if I'm just looking to have fun, I'll choose Mewtwo. Sure, he's slow and easy to knock out of the arena, but he's just so much gosh darn
fun to play. Not to mention his insta-kill throw at +100%