Apple - How do I delete unwanted Apple ID's?

There is no easy way to disable / delete the Apple ID from Apple's servers, but you can delete all the personal data (contacts, calendars, mail) and then change the contact information and security questions / password to ones that you will no longer use or ever enter into a device. I would write them down and file it in a safe just in case you change your mind down the road. If you want to re-use that email with Apple in the future, you may want to change the Apple ID to a disposable email and clear all other emails from that account if you ever want to use those "real" email addresses with your actual AppleID.

• How do I remove or delete an @me.com email?
• Remove an email address from apple-ID
• http://support.apple.com/kb/HT5622

In short - you can and should delete the obsolete ID from all your devices. In the past, there's not been a way to delete an account without Apple support speaking with a service engineer to delete an account on the server side.