Panny for sure...the only brands I'd consider in the plasma industry are: Panasonic, Pioneer, Fujitsu, Sony, and maybe NEC.
I have a Panny TH42PX20U (42" HD plasma), and I love it. Never had a problem with it, blacks are VERY good, maybe a little red push (can be fixed with ISF Calibration).
Pioneer has a very good reputation--color saturation is very good, but blacks are little light.
Panasonic plasmas have the best blacks on the market--very deep, with little or no crush.
Fujitsu purportedly has the best color on the market, with good blacks as well, but a little expensive.
Sony plasmas are extremely expensive (sometimes $2000 more than competitive plasmas), but are still good displays, plus that floating glass bezel is sweet...
Some of the AVSforum guys swear by NEC. I haven't seen one in person so I can't say either way...
Something to consider: You can go and look at all these plasmas at a good shop, but be aware that most places (BB, CC, GG, etc) run their plasmas in "torch" mode -- maximum brightness and contrast, to attract buyers, but guaranteed to wear out your plasma VERY quickly. And when you do buy that plasma, be sure to tune the picture right away (turn brightness and contrast WAY down, and use a calibration disc like Digital Video Essentials or AVIA). Good luck!
EDIT: Just realized you weren't specifically looking at plasma displays. In terms of RPTVs or CRTs, I believe that Samsung has a really great reputation, especially with their DLP models. Mitsubishi is also another good company in the RPTV market.
Apex was right...viewing distance and budget are going to be very important determining factors as far as what you can/should buy. For most medium sized living rooms, a 50" is just about right (my 42" is in a small room, with a viewing distance of about 7 feet). What you don't want is to buy some huge screen for a short viewing distance, only to get a screen door effect.