I just got a new Samsung HL-R5067W 50 inch DLP and noticed a delay that I think is common and thought worth mentioning. I have an A/V Receiver into which I have a DVD, VCR, Cable/Tivo. The cable HD signal goes direct from the box to TV. The AVR then has a single output to the TV so all video/audio (except HD) goes through the AVR. When I use surround sound speakers through the AVR, the sound is a fraction of a second earlier than the video/sound on the TV. I have scoured the internet about this and found many discussion groups reporting this problem. Apparently, with all the microprocessor work that DLP TVs do, there is a small but noticible delay. So - the TV video and sound, while synched to each other just fine (which I understand was a problem in older sets) lags a bit behind the sound coming from the home theater speakers. There has been a lot of discussion on other boards that this problem is also evident for people who use video games (Xbox, PS2) in that with fast moving games, the lag becomes quite noticible with delays in response. There is no workaround that I have found for gaming. However, for the surround sound, the best "fix" is to have all components go direct to the TV using the AV inputs and then have the TV audio output (mine has digital optical and RCA ends) to the AVR so the sound coming from the AVR is "post-processing" in the TV and should be synched.
I've read all kinds of posts about changing the interlacing,etc and things i dont understand to improve the lag time, but apparently this problem comes with the technology and varies between different companinies from a few miliseconds to 200 miliseconds or so.
Some high end AVRs have an option to set a sound delay for just this reason. There are also Sound delay devices as well. But I think running everything through the TV is probably better anyway since the DVD video signal should be clearer going direct to the TV. Also, those "fixes" wont do anything for the gaming issue.
When I called Samsung about this, they pretended that this was news to them. However, on other boards it seems this is common knowledge in the industry. Apparently, the units with better pictures tend to have more delay because of more processing.
Hope that helps - and Im interested to hear other peoples experiences and other brands.