For what you want a BMX would probably work well for you if that's what you want. There's a style of bike growing in popularity calle 'minivelo' which use 20" wheels but otherwise have everything else a 26" or 700c ride would have, so I guess a BMX is like a single speed mini velo. The only thing about choosing a BMX over the others is if you have friends that ride hybrids, you may not be able to keep up. In your shopping around be sure to check out used bikes as you can find some really good deals.