I am a fan of the SSR SR250 since it seems like it can really take a beating. I have a comparable bike right now and have put it through hell with no problems to show. In my opinion the bike is a perfect commuter/trail rider combo, but it wont be able to keep up with full dirt bikes when riding the trails.
I noticed you didn't specify a budget or brand preference. I assume you are looking at china bikes only, but if not I would HIGHLY recommend a Suzuki DRZ400sm or Yamaha WR250R. My next bike is 100% going to be the DRZ, I just need the money to make the purchase
