Generally plasma will give you the better picture but not so good in bright rooms and they'll use a bit more power as well. We don't have the TV on during the day so that isn't an issue for us. LCDS look (to me) very over processed and 'not real' whereas plasmas look more natural. The LCDs are easier to see in a bright room/showroom.
There's no such thing as an LED TV on the market yet. OLEDs are on the way but still pretty expensive AFAIK. When you see LED TV's being advertised it means that it is an LCD TV that is backlit by LEDS rather than fluoro tubes. Plasmas and OLED's are self-lit.
Here's a good aussie website for you to browse:
http://www.dtvforum.info/
We got a panasonic plasma about 4 years back and have no complaints.
