Damn. This is a difficult choice...
Do I go with the sword-breaking fist weapons, the Katara? A vanilla shortsword? A big freaking longsword? The range of boomerangs and Chakram? The power of an axe? How about a Dao sword? A Katana? A Naginata? So many choices...
If we're going for the unrealistic, I've always like the design of Tidus' swords from Final Fantasy X, with the notch at the end. I always thought that a slashing attack from that thing would gouge out a lot of flesh. Or, maybe, Lightning's Blazefire Sabre from Final Fantasy XIII. So much better than Squall's Revolver because it ACTUALLY SHOOTS. And it can do so rather quickly, as evidenced in a certain boss fight that is to far away for anyone but Lightning and Sazh to attack with a physical attack.
On second though, make me a mime/jack-of-all-trades who can wield most weapons. No matter what I wield, though, I'd pair it with some sort of magic/energy pistol.