I agree with Dave that it's your source, not so much the television that makes a lot of the difference. If you have a Blu-Ray DVD player or Verizon Fios or another quality source, then you're well on your way to getting excellent picture quality.
I recently purchased a 52" Samsung 52A650 LCD TV for around $2300 at Amazon.com and love it. With my upconverting Oppo DVD player, playing regular DVD's is a real treat. With my Comcast box, it's hit or miss, depending on the channel. ESPN in HD looks fantastic, while some of the non-HD channels (and even some of the HD ones) can look a little soft and pixelated.
To me it came down to the Samsung and a $2000 Panasonic 50" plasma. They both look great. I think that the differences between LCD's and plasmas have been steadily eroding and they're starting to converge. Buy the one that looks best to you.
And don't spend too much money on HDMI cables. Recent discussions here on Audiogon have confirmed my suspicions about these glorified network cables: The inexpensive ones work just as well as the expensive ones. I got mine from Monoprice (even the 25 foot ones that I wired through the basement and walls) and they work fine.
Enjoy,
Michael