Another miata owner here...
I bought a 2003 with 30,000 miles on it that was in truly excellent condition for $8,400 in April of 2009.
I love how extremely reliable and cheap to own it is. It's a blast in the tight stuff and handles the highway just fine as well (it pulls in top gear at 80 mph).
It take a lot of skill to drive fast though...as it really only makes power over 5,000 RPM and redlines at 7,000, so. I've driven with friends that I was able to keep up with for the first few turns, but once a straight came that lead to the next set of turns, I could no longer keep up.