There's nothing wrong with driving a Civic or Miata. I'd be tempted to go with the Civic. Lots of parts available, cheap to run, but fun with a manual transmission and good tires.
Have it inspected by an independent mechanic before you buy.
Ok so I am a guy. A little skeptical about these two little cars because they're not too "manly" I've always wanted a convertible and i've also wanted a civic. They both have great reviews. The miata has a few little performance parts which is a plus. I'm looking for a fun quick little commuter car. If anybody has any opinions or experience with these let me know.