For example, I would like to have my desktop/WMC set to 1080i by default since this is the resolution used by most of TV broadcasts (USA). When playing a DVD (I use MediaBrowser with TMT and/or WMC player), somehow set the resolution back to 480p, 59Hz and then return back to 1080i once finished. The same for Blu-Rays, using 1080p, 24Hz.
Right now I just leave WMC set to 1080p, but unless I send the original Live TV resolution to the TV (1080i), I see dropped frames here and there which is quite annoying. But of course I don't want to see Blu-rays at 1080i :-)
My Video card is an Asus GT430 (fanless) and my TV is a LG 6700.