I too have been looking in to purchasing a new flat screen. I've pored over reviews, browsed endless consumer sites, and visited Best Buy about 40 times. Here's what I've figured out so far:
The plasma's picture quality didn't knock my socks off like I thought it would. I looked mostly at Panasonics, as they got the best reviews of the plasmas I could afford. So, that combined with the higher energy usage, and heat output, kinda ruled them out for me. Price is nice, though.
That left LCD's, and the latest iteration of those, the LED-LCD flat screens. My parents have a 50" Sony, but I have to say I wasn't real impressed by the picture quality of these either. Blacks weren't real deep, and the processing wasn't very good. Not sure if it was a 120 or 240 hz, but I think it was 120. After doing a lot of research online, I decided to look mostly at Samsung, and LG, as they got consistently good reviews from consumers and electronics sites. So I picked comparable 46-47" LEDs from each manufacturer, and went to Best Buy to check them out. The Samsung looked just fine by itself, but compared side-by-side with the LG, it lost out. The LG kicked it's butt in every aspect (color rendering, motion processing, black depth). It really looked good! Here were the 2 I compared at Best Buy:
http://www.bestbuy.com/site/Samsung+-+46%22+Class+/+1080p+/+240Hz+/+LED-LCD+HDTV/9293579.p?id=1218076082869&skuId=9293579
http://www.bestbuy.com/site/LG+-+47%22+Class+/+1080p+/+240Hz+/+LED-LCD+HDTV/9318623.p?id=1218084410226&skuId=9318623
IMO, the LG won out based on picture quality, and price. But you wouldn't go wrong with either one, methinks.
EDIT: Furthermore, the LG is a back-lit LED screen, whereas the Samsung is edge-lit. The significance of this, as I understand it, is you get a better picture quality with back-lit screens, but sacrifice thin-ness of the panel (edge-lit screens can be made very thin, nearing ~1" now). So the LG that I looked at comes in at about 4" thick. Not so great if you're looking for a sexy, wall-mounted TV. But if you're considering plasmas, you kind of give that up anyway.
My final verdict: I'm going with the LG 47" noted above. It passed the eyeball test, it's cheaper, and I'm planning on getting an entertainment center for it anyway, so thin design is not a huge selling point for me. The plasma was a contender, but I just couldn't get past the energy use/heat issue. The Samsung 46" I referenced above would be choice #3 in my book. Price was the primary deterrent, especially when you consider what you get for the extra $600 (basically a 1.2" thin panel) over the LG. Hope this helps a little, and keep us posted on your decision...