An All mountain board seems right up your alley. Every major manufacture makes a great board that fits what you're looking for.
Never Summer SL
Rome Agent or Anthem
Burton Uninc or Custom
Atomic Cold smoke
Nitro has a couple that would fit the bill, so do Gnu, Lib tech, and Ride. I would say get a skate banana, but those are impossible to find until the '09s come out.
Sierrasnowboard has some killer deals right now on 08 boards, and you most of your local shops are probably trying to get rid of their 08 stock here soon. I just bought a Custom for $250 on sierra, but there are atleast a dozen boards that are designed for exactly what you are looking for, so shop around!
Size wise, I'd say you'll probably want something around 152-156. Shorter will be flexier and less stable at high speed, longer will be a little stiffer, but more stable at speed. Also, if you are still growing, err on the longer side.