I have a 65 in Mitsu Diamond Series HD set and love it. If you want the most HD goodness available be sure to get a good outside antenna unless you're very close to your broadcast city. Hope this doesn't confuse you too much but there are about 16 different HD and SD formats, even though most of the local stations are broadcasting an HD signal, not a lot of the material was shot in HD. There are differences in quality between the different networks, no uniformity to speak of. Fox is about the cheapest and their picture shows it. Where it really shines is with a full HD picture and HD cameras like with the Olympics, Super Bowl etc.. So the best bang for the buck will be using a regular TV antenna. You can also get HD on dish network, am not sure about Direct TV, don't use em but they probably do. For me right now it's not worth 600 bucks more for another dish just to pick up a couple of HD channels when a top of the line TV antenna is about 100 bucks. I get CBS, ABC, NBC, UPN, FOX, UPN and TBS and a couple of others, there is nothing that can match the picture of a full on HD broadcast.
For the best information on HD broadcasts in your area and what's actually being shown in HD format check out Titan TV. It's free and a great guide to HD, Satellite etc.
http://www.titantv.com/
One word of caution most of the HD sets out there whether projection, tube or plasma *will* suffer some burn in unless you give the screen a workout by not leaving it in standard 4:3 for regular broadcasts and not leaving *any* static image on the screen period. The new DLP sets that are coming out are the only ones that are immune to screen burn in. They are still not ready for prime time in regards to pricing, maybe in a couple of years.
I love my Mitsu, wouldn't trade it for a plasma or tube (too small) tv.. when the time comes will probably buy another Mitsu and get the DLP version. In the meantime this one is still working great after 3 years and I've never had to get it serviced.