I use Ritek and have never had any problems and the price is great. A lot of people are big on the high end media but I don't see any difference except that they cost 6x's as much.
I would have to agree with Cachorrao, I use nothing but Ritek g04's and haven't had a problem yet...knock on wood...
I have used TDK, Fujifilm and Memorex, and they have all worked just fine. I have never had a failed copy due to media problems. I pick the least expensive at the purchase time. I'm using a Pioneer DVD+-RW AU06. sb.