Any of you Techies know anything about rendering video?

What format works best in a standard DVD player for widescreen or 720?

Can you render in 1080 burn to a standard DVD and play it on a blue ray or do you have to burn a blue ray even though the file is under 4.7G?

Lastly, what format for Blue Ray?

I have tons of movies, just figured out sony vegas pro and now its time to render and burn.

Thanks

GEM. Try This

Thanks Grahm, but that's a bit to generic. I'm looking for specific resolutions, frame rates and compression settings.