I have the sony 500 drive. After much trial and error. Princo, Ritek 2x and 4x, Memorex 4. The brand that has worked flawless for me is the TDK 2X dvd-r media. The memorex and Ritek had a lot of problems with full burns, as the media was written closer to the edge. I still use my spare Memorex if the burn is no bigger than 4 gigs and it works fine.
I have a DRU510A and TDK 2X work great for me as well. I just tried Imation -r and they are working great too but I have read that people have trouble with Imation
With firmware 2g, I haven't had any problems with the following medias: - Maxell DVD-R 2x - TDK DVD-R 2x - Hewlett-Packard DVD+R 2.4X - Hewlett-Packard DVD+R 4x - Packard-Bell DVD+R 2.4x