right off the bat, i would not suggest plasma.
*pros - bright picture, vast viewing angles
*cons - burn in (not as much an issue with newer sets as before, but still an issue), really hot near screen, picture will fade over time-no repair for this.
rear projection (LCD or DLP) is the best bang for the buck. gives you incredible picture at a fraction of the cost of most flat panel LCD and plasmas. if you can stand a 14" or so depth unit and are not concerned with mounting it on a wall, rear projection is the way to go.
*pros - low cost, great picture, low weight for their size
*cons - not wall mountable, bulb has approx. 3 year life span-replacements are between $200-400 at this point (next generation of bulbs will last approx 10 years)
if you want flat panel, LCD is the answer. you're going to pay a high price for it (that's why i suggest rear projection), but it is ultimately the best choice.
*pros - fantastic picture, great viewing angles, wall mountable
*cons - expensive
any issues you are going to have with the picture are going to be evident right out of the box. keep in mind, with these newer sets, the best picture is not the default setting. some calibration is needed to fine tune the picture.
i personally wouldn't get too carried away with 1080p right now. unless you are going to buy a Blue Ray Disc player or PS3 anytime soon, there is no need for it. save yourself a lot of cash and get a 720p as it is the standard in HD now. 1080p will be one day, but by then you can move your new tv into another room and get a 1080p for a nominal price.
that's the abridged version......let us know what exactly you want (wall mount or not necessarily), how much you want to spend, your ultimate intentions, etc.