A DRZ would be a great choice, or maybe a KTM 4 stroke. Just think, you could get into doing the dual-sport rides (sounds lame but they are a blast!), and then enduros maybe? A dualsport bike is the way to go in my opinion, riding around in a circle on a track is fun for about 30 minutes, and riding illegal spots is getting more difficult every day. There is an event just about every weekend around here, (NJ, or within 2 or so hours drive). You can find kdx's and many other 2 strokes on the classifieds that are already street titled if you want a used bike. Good luck!
P.S.- If you need someone to hit the DS rides and enduros with, I'm in NJ and could always use another riding buddy!