I too had problems in the past with stick on labels. Particularly with discs that I played very frequently. I never damaged a player, but my computer would have problems reading the discs after a while.

I recently purchased an Epson R200 printer ($65 on clearance) and a CIS ink kit. It was more money than I wanted to spend, for sure, but it beats stick on labels any day as well as the "sharpie" method. I'm in the process of printing labels for my entire SW DVD preservation & fan edits collection, as well as my 36-disc MST3K collection. I'm about 1/3 of the way done with printing them all, and I've barely even used 1/10 of the 4oz. ink bottles I got with my CIS kit. It was a lot of cash up front, but in the long run I'm saving a lot of money over using regular ink cartridges, or stick on labels for that matter.

I haven't tried using any coating spray though, as my dorm room isn't the most ideal place to be spraying chemicals everywhere. I've also heard that sprays can get onto the data side of the disc and damage it if you're not careful. How true is this?