Some people swear by Verbatim, but I've had success with plenty other media, just close all other programs on your computer and DON'T touch it while it's burning.
I've burned 3 games successfully using Sony DL dvd's, but if you want the extra comfort to know that you won't ever coast a disc, use verbatim. I also have a samsung ms 28 so it probably depends on your DVD drive as well.
The dye in Verbatims(Made in Singapore) have less strain on the laser in the 360 drive. Other brands have been known to burn out laser in just a couple of months. Verbatims are known for the quality.
This is a purely theoretical question, since I've got no plans on modding the one 360 in our house any time soon (the fact that it's not mine is a bit of a damper, too).
Back in my PS2 days... or, at least, back when I was still somewhat interested in playing backups of my damn expensive imports on my PS2 (shipping was such a bother), I remember reading through those DVD media lists, saying which ones were better and producing non-coasters and such. Taiyo Yuden, Verbatim, and Sony were always at the top.
Would that be the case with the 360? Or is it strictly Verbatim, what with a different laser module and such?