Don't hate it, Vid. Really. There's no point to hating the term used to describe a person's best character. That doesn't even make any sense. Also, good luck out there if you don't plan on getting particularly good at using one character...
Also, I'm with Suffix. Rockets are awesome. Also, there's no saying what character you'll be best at using. You can't really just up and decide, "I'm best with this character," before you ever use them. You can say, "I want to be best with this character" and take it from there, I guess.
That being said, I guess I'll just predict. My current mains, Ness, Pikachu and Yoshi, seem to have experienced de-nerfing from Melee to Brawl, from what I can see in videos, so it's highly, highly likely (more likely than Sakurai putting a screenshot involving a Kirby character in the next update) that they will stay on my list. I want to pick up Wario. If I do I will NEVER use the overalls that so subtract from his personality. I will probably pick up Lucas, being a Ness user... after the Mother 3 fan translation is finished. But to me, he seems like training Ness--easier to use, but a little less powerful.