Sinon.
Asada Shino (or Shino-non to her closest friends) is the real-life person (who is afraid of guns). And has black hair. And wouldn't be caught dead showing any skin. Her game character is a sort of therapy for her. While most gamer characters have a different persona in the game from real life to some degree, Asada's disconnect from her character is probably the furthest (aside from An Shoji/Tsukasa in .hack//SIGN, which inspired SAO) due to a childhood trauma (also the case with Tsukasa, but different trauma) causing her to create a character which is vastly different from who she is IRL. The deadly sniper vs the gun-fearing schoolgirl. Tsukasa only tops that by An Shoji convincing herself she was a boy in the game (though, to be fair, her IRL persona was separated from her character by the rogue AI Morganna).
Source: book reader, and fan of the franchise(s) since 2001-2002.