(1) How big is your main HomeTheater TV?

I have a 42" Mitsubishi WT-42311 widescreen RPTV.

(2) What kind is it - DLP, CRT, etc....

CRT

(3) Are you running HDTV content?

Yes. I have an HD cable box from Bright House Networks and get ABC, CBS, FOX, PBS, Discovery HD, INHD1, INHD2, HDNet, HDNet Movies and Sunshine (Florida sports channel). I should have ESPN, NBC, WB, and UPN soon. HBO and Showtime are available, but I dropped them.

(4) Any notable impressions/cautionary tales about big screen that the rest of us should know about?

A CRT based RPTV is susceptable to burn-in, so I stretch TV shows that aren't broadcast in widescreen. The best picture you can get from a big TV (not tube based or a projector) is from a CRT based RPTV that has been ISF calibrated. It's also the least expensive. This was the best choice for my conditions (I had to fit it in an existing entertainment center) until I have a dedicated room with a projector. You can see some photos here.