Gotta second the kTm 200's. FWIW- I've ridden new 250 2-stroke MXers, older (and heavy) 4 strokes, and the kTm 200 (although very briefly), and found that the kTm had plenty of power for my lard butt. They're light, nimble, well suspended, and reliable. Remember, Shane Watts consistently beats out guys on much larger, more powerful machines. 90% rider, 10% bike is how the saying goes.
Find one that "feels" right, hopefully by actually riding them, not just sitting on them at the dealer. I can't ever remember any dirtbiker saying "no" to a request to try his or her ride. In fact, I don't remember having to ask much. Just express interest, that you're currently looking for something different, and 9 times out of 10 they'll offer before you have to ask. :cool:
I'm real antsy to try a KDX, and a kTm 300, and on and on.... I'm going to a DRN Spodefest here soon and can't wait to try out lots of different bikes (currently bikeless and saving my $$$). Good luck!