Probably Bowyer. Love the design and his weird speech pattern made him even more memorable. It's even funnier that his Psychopath message heavily implies that he's faking it but, seriously, why? It's so nutty. I remember as a kid I saw his picture and thought he was pointing with his middle finger so I took up the habit too. Needless to say, that was a habit that was broken quick when the adults in my life picked up on it.
One thing that I don't think SMRPG gets enough credit for is the foreshadowing of its bosses. "Watch out for Belome." Who's Belome? *later* That's Belome?! They do this a lot: Booster, Bowyer, Blade, Czar Dragon, King Calamari, and of course, Smithy. It also does a brilliant job of blindsiding you with bosses that make you go WTF: Yardiovich, Knife Guy and Grate Guy, Bundt and Raspberry, Mack, the Axem Rangers, and pretty much the whole Factory. Bowyer's kind of a combination. You expect this Robin Hood-esque sharp shooter but, nope, it's just some weird talking psychopath who's firing arrows randomly because **** Rose Town I guess.
My favorite video game is SMRPG although that should be self evident. It's basically Chrono Trigger, DKC2, Megaman X, and pretty much the entirety of the Smash series after that.