Sarhan, I'd like to hear why you think DLC is unlikely in Brawl since you probably know the most about it. I'm not aware of all the reasoning behind it.
As far as I know, the Wii doesn't have enough memory to support a ton of DLC. Characters take up a nice chunk of memory so that's out of the window. That's why you can't download stages made by others and submitted for the daily stage thing they have planned. That's also why you'll need an SD card if you plan on building a lot of stages of your own.
@Belross: All of those "X can kill Mario at Y% at the center of final destination" things are based off of Mario just standing there and not DIing or trying to get back on to the stage. It just basically shows how much percentage Mario needs to have before the move can potentially knock him off the stage (and I believe the move has to be fully charged in case of a smash attack).
Oh, and quick questions for you. I heard that Ganondorf's warlock punch grants him super armor and Captain Falcon can change the direction of his falcon punch mid charge. Are these rumors true?
EDIT: Nevermind the Captain Falcon thing. Just saw a vid showing it works.