Here's two that nobody has mentioned, but I've always thought about for just your purpose (single handed fun sailing):
Taipan 4.9 uni
Nacra/Inter 17, regular or R
Both boats have a great level of performance for the single handing sailor. Both boats can handle taking an extra person along for a ride. Both boats have the option of using a spinnaker when you're ready to try that (believe me, once you do you'll be hooked).
Nacras are pretty darn reliable. Most things you may need a dealer replacement for could be shipped to you.