CD-R media is so cheap now days, most companies don't even put an effort into quality. I think it takes too much effort to hunt down a place that sells good reliable CD-R media. It is easier to buy random stuff from big name media companies such as TDK, Fuji, or Memorex from your local computer store. I say random stuff because those companies actually purchase the media from a different compnay that specializes in manufacturing the CD-R media. In my experience, most CD-R's are more or less the same. If price is a big concern, buying something next to the cheapest might be just as good as buying the ones that are much more expensive.
If you want something reliable, I think Taiyo Yuden and Ritek are good. However, they do not directly sell their CD-R media to the public, but to wholesalers and blank media deistributors such as TDK and Fuji. There are some small online stores that specializes in selling the media directly from the manufacturer to the end user in bulk quantities.