Here's a good article on the whole 1080p thing:
http://www.hdtvexpert.com/pages_b/reality.html
It's from last year, but I think it's still relevant today.
I own a Panasonic 50" Rear-Projection LCD Display. As for HD content, everything looks awesome. But no matter what, your picture will only be as good as your cable/satellite company can provide. Every now and then the HD stuff will artifact and there will be occasional pauses. This is due to my cable company and/or the equipment they supplied me (Moxi DVR). I've had this setup for over a year now and have been very happy with it.
Now, if only we'd get this whole HD-DVD/Blu-Ray thing situated... what a mess that's turned out to be. The blu-ray camp is hurting pretty bad right now, but could possibly make a comeback later this year with the PS3 and better players (although the price's are a major "ouch" factor). HD-DVD had a very shakey start, but they have time on their side to get things perfect. Much like the whole DVD +/- thing, I think the only thing that will decide this war is a combo player.