I'm with most everyone so far. For my personal uses like backups, I use a 'Sharpie' and write directly on the CD.
But I do agree, like for training or presentation purposes, a label is alot better - for professional image and beats writing the same thing 50-60 times repeatedly.
I've used the CD Label Creator that was bundled with my Roxio EZCDCreator package.
For the media, I've used the "after Burner matte refill" CD Labels made by Avery. To center each one, get an applicator like a stomper. For alot of labels in a short time, it really helps.
I rigged an old empty spindle. [that hold the bulk 100 CDRs I get as Costco] I put the label down upside-down first. The carefully place the target CD -face down - on top of it. Kinda hokie, but works!
Again, for alot of CDs to get labeled, get a real applicator.
Hope this helps.
Danno