Weasel said:
Is anybody broadcasting in 1080p? If not when do they plan to and does the 720 look worse on a 1080p television??
There is currently no 1080p source (at least that I have heard of) outside your computer. Apple has posted a few 1080p trailers and other gorgeous 1080p footage on their QuickTime site. I believe there is some WMV 1080p content available as well.
General consensus is that broadcasters will not adopt 1080p anytime soon because they'd rather give you quantity (i.e. more content) than quality. Your first non-computer 1080p source is likely to be the Sony Playstation 3. I don't know if it's been established that the PS3 will de-interlace Blu-Ray movies (which will almost certainly be 1080i), but Sony has said that games can be 1080p.
The math to go from 720p to 1080i/p is very simple (the uncompressed data stream of both formats contain an identical amount of data). With current technology, there will be almost no discernable difference between viewing 720p sources on a 720p-native display and a 1080p-native display.
Make sure you read the specs on your display very carefully, though. I don't know about the particular ones you're looking at, but some of the currently available 1080p sets will only take 1080p on a VGA/SVGA-style analog input, so you might be out of luck with anything but a computer anyway.