I used this gift tag once before bit did a pretty poor job of it. I smudged the writing, made a spelling mistake and recycled an inappropriate CD (what self respecting Dinosaur Jr fan wants a Nelly album gift tag?!) I think this is better!
For the gift box -filled with CD's, a t-shirt, badges, guitar picks, etc I have used a cool metal box that I have recycled from it original purpose of a perfume gift box. To theme a box I could recommend covering a plain box in old music manuscript, band posters, music magazine pages or you could use old CD booklets. Old band t-shirts could also be made into gift bags if you have the sewing skills.
For this CD gift tag I have used a some letter stamps and and ink pad but you could also use a permanent marker and write the message by hand. I have simply attached the ribbon to the box and threading the CD onto this but you can also attach the ribbon in a traditional manner. A musical alternative to ribbon would be to use a guitar string.
Other music inspired gift tags could be old concert tickets (although most avid music fans keep these so check before writing all over one!) and old iTunes gift cards.