Q: I have a MacBook that supports up to 1900x1200, and a 42" plasma HDTV. I already have an Apple mini-DVI to DVI-D cable, but does HDMI or VGA or S-Video gives better quality if my HDTV is compatible with all of them? I am aware of the lower resolution on TVs when compared to monitors.
A: You're right, TV's do have lower resolutions (marginally) but that won't make much difference. The DVI-D is the best signal quality of all the formats you've mentioned, so use a DVI port if you've got it, HDMI is the next best thing, with VGA and S-video trailing way behind. Just don't forget that if you want audio you'll need a separate cable as well.