When selling CDs, you'll want to be sure you include in your item description whether or not the CD has explicit content or lyrics.  Also, it's a good idea to include a disclaimer that you are not responsible for cracked jewel cases during shipping.  Many CDs, especially the ones you get from wholesale lots, have cuts through their spine of the jewel case or will have the bar code cut out.  These are usually store diplay models or returns that are auctioned off in wholesale lots.  They make for a decent turnaround if you can sell enough of them.  I have found CDs sell for more than DVDs simply because you can't go to Blockbuster or sign online to Netflix and rent a CD. 

If you're planning to do CD auctions, I suggest you do them in bulk to maximize profit.  Also, preparing them for shipment in bulk is much easier, so I recommend listing them 25-50 cds at a time.