I wouldn´t take the risk. A notebook in Ibiza ?!
Actually I´d bring as few stuff as possible. It´s more practical, specially if you happen to be off your face most of the time.
Instead of listening to your own CDs, leave them in Köln and let the fresh music from Ibiza impress you and be the soundtrack to all the parties and moments you´ll live there. So when you come back to germany you can download the new anthems and they will take you back to the island...
Enjoy yourself !