Sharon, you're right about the adhesive corroding the reflective layer on the CD. I can't remember where I read it, but when (if) I find it, I'll post the URL. However, I'm sure that the label manufacturers have addressed this problem by now.
Equally as bad is using xylene-based inks to write on the CD. It's best to use alcohol or water-based ink and to use CDs with a coating to write on. On the same site, I read that some of the early music CDs died because of the inks used to label them. Remember, the reflective layer on the CD is very thin (~ micron). It doesn't take much to destroy it.
Another problem is caused by placing labels off-centre. This can throw the CD out of balance and damage the CD-reader. And as y'all know, once the label is stuck, there's no way that you can move it without destroying the CD.