I would say to definitely check into a KDX200 or KDX220R. It is a trail bike. It might be a bit zippy for a new beginner at first, but it shouldn't take long for you to grow into it. If you went with something like the Honda CRF230F or the new 2005 Yamaha 230, you might grow out of those in about a year, then have to sell it to get something with better brakes, suspension, motor, etc. Definitely check into the KDX you mentioned, but don't buy something that you are going to have to work on to get up to snuff. You will have enough to worry about as far as just riding. Being a mechanic and being a rider are two different things.
RoostRider made a great point. Put about $500 of your budget into safety gear. Also, make sure you have some way to store the bike when you are not riding it, plus a way to get it to the riding area. For example, if you say, "I have a truck.", I would ask, do you have a pair of tie downs and a loading ramp?