i don't know... but my cheap-car-insurance.com.au website keeps making me money everyday.
I recken development is the best way to go... park all your sites and then start developing your online real estate.
Someone I know has just purchased this recently and got their first site up and running. I think it's really pretty good from what I can see and what he has said. He's really happy with it, I am looking at the "built in SEO" fairly critically (think you'd need to do a little yourself when you were comfortable with it) but am pretty impressed overall. I'll see if I can get his permission to post the website or PM you.
I think development is always the way to go - but that may be because I don't own any blue chip domainers domains