My mains will probably still be Falco, Marth and Mario, with Diddy Kong and Zero Suit Samus joining their ranks.
Let me make this interesting by listing mains from other games.
Street Fighter II: E.Honda, Vega
Street Fighter Alpha: Cammy, Sakura, Karin,
Capcom vs. SNK: Nakoruru, Ken, Dan
King of Fighters: K', Athena, Terry
KoF Maximum Impact: B. Jenet, Terry, Alba
Killer Instinct: Spinal, Orchid
Mortal Kombat: Liu Kang, Sub Zero
Marvel vs. Capcom: Wolverine, Spider Man, Sakura
I've played Guilty Gear, but I don't remember half the people in that game. All I know is that the AI sucks and the game is easy.