Apple's own DVD-R disks work the best (available in the Apple online store in both 4x and 8x speed), but I find that Verbatim media also works well with my SuperDrive. Maxell/Memorex seem to be the least reliable on my machine.
Of course, as with anything else, your experience may vary, and it's impossible for anyone but yourself to figure out which media works the best. We can only recommend what works best with our systems, but even someone with an identically-spec'ed machine as yours can still experience very different things with identical media.