To the person who talks about Jiggly Puff...forgot your name. One of the simple ways to get the sleep in is by tilt attacking upward, if the opponent is close, say for example: If you roll behind an opponent, and you tilt upward to attack, you can send the opponent in the air, this works on characters who have poor aerial recovery, or even average aerial recovery(it won't work on characters like Samus, Peach, Marth, and others who recover quickly) jump up and sleep, timing between characters is a must, because some may only require you to short hop, or baby hop into the sleep, it should be a guarantee sleep hit, even if the opponent tries to tilt, they can't get away.
However, this tatic should only be used at low percentages, say 0-25%, it's an almost guarantee kill. Even on a stage such as Final Destination, they will die from it. Sleep attacks can work in many different ways, the way to use the sleep attack, is to not just "use" it by itself, for by doing that, you will definetly be vulnerable, it is however not impossible, for I've experienced it first hand by Jiggly Puff players who has almost mastered the rest attack by itself, however if your timing is not mastered yet, learn to utilize it in combos. There are many ways to use it, go to www.smashboards.com and find a video on Jiggly, there should be some combos in there that involve rest combos with Jiggly, particularly one is on there DDC server, which has Tetsuya doing some very nasty combos and aerial combos into the rest.
As for me, my favorite characters in the original SSB was Ness, and Link, while in SSBM for the GC, it's Link*, Sheik, Marth, and Peach wink . I've been in tournies for this game...infact in alot of tournies for other fighting games already, great game, true this game is supposed to be a party game, but it can be a competetive fighting game.