I have a 50" samsung plasma it's about 3 or 4 years old but I love the picture. I don't know what your finances are like but if you can afford it I would get a 55 or 60", my friend has a 60" samsung plasma and I just drool over that thing!
I think it really comes down to personal preference and what you like in a picture, but if you want the best picture I would stick with the best known top brands like sony, samsung, pioneer, and maybe lg (lg's are somewhat inferior to the others imo). You might pay more but they really can't be beat. The best advice I can give you is to just go and watch tv at the store and see what looks good to you (hopefully they have an HD feed), and maybe try to play with the settings.
My personal recommendation is anything samsung plasma. Samsung has the best looking frames and best picture in my opinion. If not samsung then something plasma. I know everything is about LED tvs now but I just can't see all the fuss, I'm pretty picky about tv's and they don't cut it for me. LEDs are still just a backlit LCD tv and the picture on that will always be inferior to plasma. My biggest gripe is that I always see a faint glow around the edges when the screen is black on an LED, and that doesn't happen on a plasma since the cells are essentially off. I believe plasmas also always have a higher refresh rate than any LCD. Plus plasma is a technology that's been around for awhile so it's generally cheaper. People will tell you plasmas use more electricity, and they do, but were talking maybe $20 or $30 dollars a year which can be offset for several years if you think about the price for an LED.
Oh and definitely get surround sound if you don't have it yet, WORTH IT!!!