If you can still find one, the best rear projection TV on the market is the Sony A3000 (google Cnet's review). There's a 50, 55, and 60 inch model. I own the 50, and aside from some SSE in brighter scenes, it's an excellent TV. They're not DLP, they're LCOS. Sony just stopped making them this year.
If you want DLP, Samsung and Mitsubishi are pretty much your only choices, as rear projection TVs as a whole are a dying breed. I haven't kept up much on the newer models, but I know Samsung has had some significant geometry problems and hotspotting with their slim DLP sets. Sensitivity to silk screen effect and the viewing angles of the TV are also major concerns when dealing with RPTVs, and if you're looking at traditional DLPs with a rotating color wheel (vs LED lights producing the color as Samsung has in some sets) you should ensure you aren't sensitive to the rainbow effect.
I'm not altogether on anyone's side, because no one is altogether on my side.