First, forget about lcd. In general, they have tons of motion blur, aren't very bright, and have poor black level, contrast, etc. Just look at a shot of the winter olympics on one then look at a good dlp and you'll see a ton more detail in the white snow and ice than on the lcd.
A good dlp or LCoS is the way to go. As far as the 720p sets go, there isn't much noticeable difference between a good dlp such as a Samsung or Toshiba and a LCoS like the JCV's. I worked at a BB and our best seller was the 52" JVC HDILA, but I never hesitated to reccomend the Toshibas and Samsungs in most circustances.
You're really going to have to go out to the various stores in your area and take a look. However, try to make sure that what you're looking at on a particular set is really HD and that you're comparing the same source on each. This is very often a problem. At my BB store, for example, the standard feed we were running to all the HD's wasn't true HD. It was digital [if the set had a built in tuner (but not digital if it was plugged in using component cables, but then it was HD, but not digital] <-- (yes i'm aware that it is confusing, stupid, etc) but very often was degraded because it was split so much.
This being said, take a look around and you'll notice what you like and don't like. Take what the salesman says with a grain of salt. You'll see some tv's with good picture but you can't stand the way the set itself looks and vice versa. In the end, you'll get the set home, hook it up, have it calibrated (hopefully), and never know the difference between it and whatever else you were considering.
*Everything said here is from personal experience. If you think LCD's look great then more power to you. From my experience, they look awful compared to often equally priced DLP's and LCoS's.
