Hi there,
In my experience, computer monitors have a much better picture than TVs. Most 1080p monitors are good quality anywhere in the 120+ price range. My main screen is an Acer H243H monitor, which is 24 inches, 1080p, matte display. I really like it due to the build in speakers and port connection options. I use it connected via DVI to my Mac Pro (along with 2 Dell displays as side monitors) and use the HDMI port for my Xbox routed through a capture card. If you enjoy your ACD, look for a matte display monitor. Many people will recommend many different monitors, I'm sure, but I find it best to go to a store such as Fry's or Micro Center (depending on your location, one or both might not exist) and really look at the display before you decide on it. Many have different viewing angles, adjustments, etc.
Good luck!
-N