Afterdawn's site (mentioned above) is excellent! Their whole purpose in life, is to help people with burning problems, with cds and dvds. They have the experience and know what they're talking about. They are based in Finland, where copying dvds and using p2p networks, aren't illegal.
The one thing that all the folks (in the know) there agree on is: "stay away from Memorex DVD media". It is manufactured by one of the worst companies, on the planet. Go there and read. I don't mean to step on anyone's toes. I'm trying to save you a lot of trouble and heartache.
Memorex and other cheap, no name brand media, may burn ok, and look ok, the first time or two you watch it. But, six months to a year down the road, when you go to watch it again, the picture will freeze and pixellate, and the sound will hang and stutter, and be unwatchable. Then you realize you have to redo a lot, if not all of your movies!
The only DL media, that we know is consistantly good, is Verbatim. But all brands of the -R's is questionable right now, because of being so new, and not having proved themselves yet.
Good luck!