Though I personally think that plasma screens look better, LCDs have the specs I prefer. Here is a breakdown:
Plasmas have a higher contrast than LCDs, meaning their darks look darker, and their brights brighter.
-Plasmas typically have a 10,000:1 ratio
-LCDs vary: 1,000:1 is common, but you can get a 5000:1, then you can hardly differentiate from plasma.
LCDs have a higher native resolution, and thus a more accurate picture
-Plasmas CAN get as high a resolution as LCDs, but that normally jacks up the price a bit
Plasmas are cheaper than LCDs for their size
-but LCDs are cheaper for resolution
LCDs have longer pixel life, meaning you can watch them longer before they start to dim
-Plasmas are usually around 45,000 hours, and get somewhat higher
-LCDs are usually 60,000 hours and higher
-45,000 is still a couple of years of watching CONTINUOUSLY, so how big a difference does this make?
LCDs are lighter in weight than plasmas, making them safer to wall-mount
-a typical wall-mount can supposedly hold up to about 120lbs, which is 35lbs more than a 46" plasma, so this might not make a difference
LCDs have lower power consumption, meaning a cheaper electric bill
Plasmas are more likely to burn-in, meaning you'll see a residual image of something left on the tv for too long, but nowadays, plasmas have screensavers to try to prevent this
LCDs usually have more inputs, for more and varied devices.
-Plasmas usually don't have computer inputs, LCDs do
LCDs have a longer refresh rate, meaning you may see some ghosting that you don't want
-Plasmas have a 5ms refresh rate, typically
-a good LCD will have an 8ms refresh rate, hardly a noticeable difference.
So, as you can see, LCD and Plasma are really fighting a war for supremacy. You'd be best, like I said, weighing what you want, and going and looking at some TVs. Sorry, there is no clear-cut winner right now.