Heh, I first started off my X-box experience by buying a bunch of name-brand media (TDK, Verbatim, Samsung, etc.). In fact, I bought a bunch of DVD-RWs since I read (or thought I read) that DVD-RWs are more likely to run on most X-box drives. To make a long story short, I failed to get any good runs with those damn RWs.
From my PS2 experience, I decided to give it a go and try the KHypermedia (Office Max - 5 for $20 or 10 for $20; you decide which one is the better deal...LOL) that has always worked with my PS2. Low and behold, it worked like a charm!
Since then, I've been able to back up pretty much all X-box games.
Keep in mind I do most of my backing up with original games and not scene releases (usually in RAR archives).
Of course, I got some Princo's now, so I'm doing backups on those. A LOT cheaper than buying DVD-R media locally...