I have experimented a fair amount connecting my MBP to an HDTV. I currently run my desktop, a Win XP machine to a 26" Sony, 720p, LCD. Have also had it connected to a 32" LCD. On an HDTV, neither XP nor Linux have an issue with being properly displayed with VGA / DVI. XP works but not Linux with HDMI (but I will note, this is really a motherboard issue that Linux has not yet overcome).
Have connected my MBP to the same monitor and to a 55" and not been able to achieve the same success. Have used VGA and HDMI only with the MBP since my current sets do not have DVI connections. The best option I have found is to use true 720p which is 1280 x 720 on both of my sets. Watching movies are OK, but text is very bad. Both, my XP and Linux boxes have no issue even with text. Tried playing WoW on it this past weekend with my MBP via HDMI. No thanks, picture was bad enough, that I would rather stick to the 15" screen than to play it on the 26". I have posed the question on this forum and a couple of others and have had no responses at all. Nor have I found anything in searching the net.
I don't have access to a true 1080 set, so have not experimented with one. In relation to 720p sets, the best I can figure why 1280x720 is best is because this is what the sets are set up to receive from standard video signals even though most LCD's native resolution is 1366x768. I think the VGA connection on TV's are an after thought for the manufacturers and the internal circuitry is not all that well designed.
By the way, 1920 x 1080 does the same on both of my 720p LCD screens.
At this time, am almost ready to get rid of the HDTV and look for a computer monitor, which should take care of the issue. My problem, is I am using that single screen in my game room for my 360 and satellite HD, so I need to find a monitor with at least a couple of component connections. Don't know if they exist or not. They didn't a year ago.
As I noted above, the HDMI connection with Linux is a motherboard issue. The only reason I really discovered this is due to not being able to get into the bios when connected via HDMI even though once you get into windows the display is fine. Linux will not even install when connected via HDMI. My own supposition is that HDMI has not been designed to pass information to a computer's motherboard, and/or the mobo manufacturers just have not integrated the way HDMI passes info into their chipsets. My guess, this is the issue with the Mac's at this time. The EFI does not interpret correctly the info being passed to it from an HDTV.
And, by the way, EFI, first develped by Intel, is their push to bring DRM to the PC platform. So, I wouldn't hold a lot by what Steve has to say about hoping for DRM free music, since he's the first to implement a DRM capable platform in the PC.