Jigglypuff players unite!
I find Jigglypuff to be one of the deadliest characters in the game with her awesome mobility, along with her deceptive range, priority, and awesome comboing and edgeguarding capabilities. All of that adds up into a character who, like Samus, has an awesome array of powerful setups and mindgames, minus the projectiles, of course.
Her offense and defense are very interchangable for Jigglypuff, who can use her mobilty not only for an offensive approach, but as a quick, easy, and usually unpunishable retreat. Her recovery skills are awesome, and she has one of the deadliest moves in the game: rest, a move that when done correctly pretty much ensures death for any character without a long-range recovery.
K, there's a bit of info on what I think on Jiggs. GoGoGo!