I am not rendering to Blu-ray, but just have some footage shot on an hv-20 and want to render it out (1280 X 720) for DVD. What do most people use as far as rendering specs?

Your video needs to be MPEG-2 to go to DVD, so just render to that. Use Vegas' "DVD Architect NTSC Widescreen 24p" option, set the bit rate to what you want (a constant bit rate of 7.5 is about as high as you should go on DVD-R to be sure of compatibility.)

I do understand that, but I was wondering if I should set it to 1280 X 720 inside of the MPEG?

That is a higher resolution than DVD can handle, so DVD architect will just recompress it anyway. Keep it 720 x 480.

thank you for that

Actually, it's only a standard DVD that requires mpeg2 vob files. But there's nothing stopping you from putting a 720p .mpg file on a data DVD. It would be playable in all computers, a PS/3, and I bet (but I really don't know) in most blu-ray players.

Obviously you won't fit much HD on a DVD. Use mpeg4 to maximize, but older computers may not play it well.