well i would definately go with bmx...with bmx you can bunny hop and learn tricks like the 180 bunnyhop and barspin in not too much time. if you are simpy looking for transportation i would get a bmx because you can have fun on your way to your destination. but then again if your going to be riing on mountains and trails, a mountain bike would be better for you. If you want reasonably priced bmx bikes i would definately check out the new mirraco 2010 bike line, and in mountain bikes you cant go wrong with konas and diamond backs. all in all go with the bmx bike =)