If you are riding street or trails. I would go with something like Primo Pro bars. When you get them cut a half inch off each side to see if that works for you. If not, cut anouther quarter inch off each side. don't go too narrow though. when your brake lever is on the bend of the bar, you've cut them enough. Bars that are to narrow can effect your balnce not only on manuels, but also in the air.
Oh! by the way. To cut your bars, you can either use a hacksaw, or you can purchase a pipe cutter from your local hardware store. If you don't know haow to use a pipe cutter, just ask the salesperson. I use a pipe cutter, because it's less work, and the cut always comes out clean.