FWIW, I spent a year trying to figure out what to get. I'm one of those shoppers that would easily regret a purchase if I knew that if I just waited a little longer, I could have gotten something better and cheaper. And while I was waiting to make a decision, the manufacturers would announce their new models and would cause me to wait some more!
I, too, narrowed my decision between the 50" Samsung DLP and the Sony GW3. Staring at both screens at a few different stores, I liked the picture of the Sony better. This is a personal preference but the Sony (as well as other RP LCDs) have a softer, matte-like appearance. Some say it's not quite a sharp looking as DLP, but I find it to be a more pleasing picture to look at. My suggestion is to observe both a movie as well as a HD video for comparison. Also, I liked the SD picture on the Sony better than the Samsung. Remember that there is still a relatively small amount of HD programming, and you'll be watching a lot of regular broadcasts. Not all stores have SD broadcasts but it's important to check this out.
I had read all about the problems with the Sony bulb and DLP's rainbow/headache effect. So, of course, I waited for the new models from both manufacturers that have been hyped over the last couple months.
I still liked the Sony picture better, but I didn't like the new enclosure on the 50" model either. I didn't see a noticeable improvement in the Samsung, even though the contrast was supposed to be better with the 8-segment color wheel. The new Sonys added CableCard & an HD Tuner, but I wasn't going to use either one, now or in the future. Other than that, there was not any reason to spend the extra money on the GW4. The GW3 was on sale and the bulb issues with the Sony had been resolved, and that's what I ended up getting.
So far I'm happy with my decision. Viewing angle is OK - the kids still lie on the floor to watch, and yet even with it's diminished brightness, they really don't care! But if viewing angle is super-important, you can always wait for the new LCD direct panels coming out next year, but they'll be at least twice as much as the rear projection.
At night, the Sony's blacks are dark gray, but the you get accustomed to it and the trade-off is the nice bright picture in the daytime. If you watch the TV at night with some lights on, it is not as obvious.
HD cable has been a bit of a disappointment. We have Cox and they are working with the Motorola 6412 dual-tuner HD-DVR, but are having major problems with HD resolution. That's a whole different story - you can check out my posts on those threads if you're interested. Anyway, hope this was a bit helpful.
Don