Haro Steel reserve
I have just ordered an 09 haro steel reserve ss and i am planning to ride 4X, DJ and street on it. they are a great frame and have awesome components. also a ss is better for this type of riding as if you bail you don't have to worry to much about anything breaking ( such as rear hangers/derailuars !! And i know this happens as i work in a bike store and have seen about 6 dj bikes in the last month come in with busted rear hangers or rear derailuars in the back wheel.
but in the end it is what is most comfortable for you to ride !!