Your style is a lot like myself. I ride all over the place looking for little things to hit or jump off. I use the sides of the trails a lot looking for fun little obsticles. I'll stop by the park every now and then but won't spend my day there. I like to rome the whole mountain. I do like to go fast but think that is relative (it's fast TO ME).
For a board, I was stuck between the NeverSummer SL and EVO, the Rome Postermania and Artifact and the K2 Turbo Dream. All of these boards should be flexy enough to play on but stiff enough to handle the entire mtn. I chose the EVO with Union Force bindings. I believe that combo would run at the top end of your price range ($650).
My binding options were the Union Force, Rome 390 and Ride SPI.
That is a good deal Sierra has running. I've read a lot of good things about the Sierrascope board too. I think you could pair that up with decent bindings and walk away for under $400.
Good luck and be sure to post your decision.