Went and looked at a '96 Honda XR400 yesterday and really liked it. It wasn't in that great of shape (maybe 7 out of 10), but the motor seemed solid and it fired right up on the second kick. The dude was pretty cool and let me take it for a spin around the neighborhood. Having not ridden a dirt bike in 25 years, it took a little getting used to, but sure seemed like fun! I think the XR400 would have plenty of oomph for the type of riding I want to do.
I'm going to to look at a '95 XR600 today, but I'm pretty sure it's going to be too big for me. I'm only 5'8" 165lbs and on the 400 I was tippy tippy toe.
Dude wants $1,400 for the 400....seems like a decent price....not great, but decent....and he didn't seem like he wanted to budge.