I did some research on this about a week ago and found that the best you can get commercially (at a B&M store) is generally Fuji. After that, TDK and Verbatim are roughly equal.
If you want the best, apparently you need to get "Mitsui" CD-Rs. I haven't seen these anywhere and haven't made a lot of effort to track them down, and they generally run about 50 cents for a disc (so comparatively expensive to other brands).
After Mitsui, Taiyo Yuden is the best. You can get them from rima.com for about a quarter a CD, which while still somewhat expensive, they are of high quality and can be used for archival purposes.
Also it helps to get media made in Japan and NOT in Taiwan - apparently the manufacturing processes are different enough that Japan's items are superior.
Finally, DVD+R is superior to DVD-R. I found a page on this...somewhere, and it contained a lot of highly technical information that compared the two types - how the pit system works, data frequency patterns, etc. I sort of skimmed it and determined that the main thing that stuck out is that +R has much better ability to handle data corruption and repair, so it is superior.
So bottomline: Get Mitsui if you can, or Taiyo Yudens online. If in a store, aim for Fuji, Verbatim, or TDK. Avoid Memorex - cheap for a reason. An added plus is to get media made in Japan. +R DVDs are better than -R.
That's what you need to know in a nutshell.
Now, burners, on the other hand.....personally I've never had a problem with either a Plextor or a TDK.