Re: TV-out - optimal resolution?
The optimal resolution depends on the tv system in use. In case of NTSC it is about 640x480 while in case of PAL it is about 800x600 (most of the time 768x576 or 720x576 for DVD). The drivers might already do some downscaling in case of 800x600 on PAL to 768x576. So something close to that could result in a good image but there are also a number of other 'variables' that are important (television, cabling, ..).
I would use the mode you like the most. When you watch a movie (which is what in general tvout is used for) you don't really notice the difference.