Which Xbox 360-compatible LCD monitor is the best size/has the best resolution for the cost?

I have an Apple Cinema Display that I was hoping to connect to my Xbox 360 for gaming, but it has an ADC connector. I would have to buy an Xbox-to-VGA cable and a VGA-to-ADC converter, which would cost more than $300. I figured I should just buy a new monitor.

Which LCD monitors on the market are most compatible with Xbox 360, support HD gaming, are of decent size, and cost less than $300?