I wasn't aware there were so many types of DVD-Rs.
Does anybody have any suggestions or recommendations on which DVD-R to get, and which to stay away from?

Here's the site that sells them:
http://www.yesbuy.net/dvdr1.html

Depends on your DVD burner. It is best to get a dual format DVD burner. DVD+RW, DVD-RW, DVD+R, DVD-R supported.

On that link the only difference i see is the burning speed. See what speed your DVD burns at. Last time i checked 4X was the standard and 8X are about to go commercial.