Let's see now... when I first got Brawl, I'd use my Melee main Samus. I also used Wario from the begining, and thought to experiment with Dedede... though I unlocked all the characters and kinda forgot about him. Later, I would use Wario, Samus and Luigi. After a while, I sort of... put Luigi to one side and make him a "for the lulz" character, because I wasn't improving with him much. D: I also hit a slump with Samus at one point, but I use her again now. After playing the very epic MOTHER 3, I also added Lucas to my mains. So now, it's Wario, Lucas and Samus, in no real order. I'm also trying to improve my Olimar. :o
tl;dr, Wario/Samus/Luigi--> Wario/Samus/Lucas.