Microcenter regularly has some outstanding deals on monitors. For example, right now, they have a deal on a 23.6 inch LED monitor for $139.00. If you were to combine that with a refurb desktop computer, such as this HP, for $179.00, you would have a fully functional media center for less than $500.00.
You can go for monitors that are sized up to 27 inches: for about $350 or so. If you want to go with a larger size, you can get 40 inch televisions that can serve as a monitor for around $500-700 or so.
Nevertheless, I would suggest that you look at upgrading to the media center computer model vice the TV/DVD model.
For television specs, I would suggest the following:
Don't even consider 720p or less. The technology is such that 1080p is absolutely the way to go. The more dots per inch, the better off you'll be.
A real key is to look at the different types of inputs that are available: you want to have a monitor that will accept VGA (so it can serve as a computer monitor), HDMI -- I would suggest one that accepts 2 HDMI inputs. One for a laptop / desktop, and one for a Blu-Ray player.
I would stay away from Plasma technology. My first preference would be LED over LCD. LED technology is thinner, lighter, and generates less heat than LCD technology. I say stay away from Plasma technology because if ANYTHING happens to it, the entire monitor is gone, while with LED/LCD, you can lose a pixel or two and the monitor is still usable.
If you are interested in Microcenter, they have stores in Patterson, Westbury, and Yonkers, as well as a web store.
Speaking of a broken plasma tv, a little levity is in order.
http://m.youtube.com/watch?gl=US&hl=en&client=mv-google&v=zhXPxx8ZrQ0