Interesting, I started a thread almost identical to this one a month or 3 ago, nobody around here really seems to know much about HDTVs as monitors, or they are lurkers, but I did get one suggestion to head over to avsforum.com as those guys are a bit more Video/Audio/Theatre oriented than the ppl here.
I posted over there a similiar thread, very few replies (no time for a Video Newbie I guess ;-) but here's the conclusion I came to with all my quests to answer this question:
* If you use your computer more than you watch movies, then you probably want to check out this monitor, 24" Sony:
http://www.ita.sel.sony.com/products/displays/cad/gdmw900.html
* If you watch DVD's/movies more than using the computer (IE, your computer is your HTPC HomeTheatrePC) then you might want to just get a Sony WEGA os similiar as your TV and use a cheap computer monitor.
I believe some High-end HDTVs have HD15 (standard VGA) inputs...