My advice would be to look at Texas Instrument's digital light projection (DLP) technology first. I was going to buy a plasma TV earlier this year and when I saw DLP and compared the price, lifespan and picture I was sold on DLP.
While I can't hang my TV on the wall (the true advantage of which eludes me) it is only 17" deep with a 50" wide screen display. Digital sources provide as clear a picture as I've ever seen and even broadcast, non-High Definition pictures are incredible.
I bought a Samsung and have been very happy with it. They made the size I wanted in a tabletop model and I'd bought a Samsung for my Mom for a birthday a few years ago and it still has an incredible picture while being problem free for her. Since I bought my DLP more manufacturers have seen the light (pun intended) and have begun producing DLP sets so you'll have more brand choices than I did. That having been said, I'd certainly suggest you give them strong consideration based on my experience.
I tried to buy mine locally from both Best Buy and was even willing to pay something of a premium to do so over mail order. I've bought a lot of stuff at Best Buy over the years and like them so I went to the manager there and offered him the opportunity to sell me the TV within $300 of what I could buy it online and they declined. I ended up with it delivered to my door for over $1100 less than the then retail price.
As I said, I like to buy locally, but even with their best offer to me I was going to have to spend over $700 more for the exact same item. I guess I don't like to buy locally quite that much.
Good luck with whatever you decide. I hope this helps. /forums/images/graemlins/smile.gif