Mario - An all round character especially good with acrobatic attacks and edgeguarding.
Luigi - Besides his wavedash and SHFFLs I see no real way to be good with him.
Link - Can make good combos, and his range is pretty dang good, but you'll have a hard time not to get with his slowness.
Samus - Techniques galore! An all-round character with some very spammable moves.
Jigglypuff - Amazing control and arials. But she's really too much of an lightweight. A real pain.
Yay! Random character judging!
Fox - Overused.