Conclusion

Using copy protected distribution media is a bad idea, for the following reasons:

1. It increases the production cost of the software distribution media.
2. It increases the number of technical support calls.
3. It decreases customer confidence in the software product.
4. It increases the level of customer aggravation when the media fails.
5. It does virtually nothing to deter software piracy.

In short, copy protection causes problems for the software distributor and the consumer, and has almost no effect on software piracy.

Bibliography

Other references:

CD Protections - This is the best reference I've found on CD copy protection methods and tools. It appears to be updated when new tools appear.
The Dark Side of Copy Protection (2/17/2002)
Have Consumers Gone Spineless? Part 2 (1/25/2002)
PC buyers face product deactivation (9/24/2001)
Copy Protection: The Audio Industry's Dirty Little Secret (1999)

Victories against copy protection:

Fair Use Foes Lose Another Battle (12/23/2002)
DMCA Shows First Dint: ElcomSoft Found Not Guilty in Dmitri Skylarov Case (12/18/02)

Audio:

The pen is mightier than copy-protection (5/13/2002)
Philips Burning on Protection (2/4/2002)
Copy Protected CDs (3/27/2001)

Successes against software pirates:

Nintendo nabs pirates (2/11/2003)
DrinkorDie pirates plead guilty (3/4/2002)
IDSA sues pirates (2/14/2001)
IDSA's Pirate Hunt (8/16/1999)
Half-Life Brings Out the Evil (11/25/1998)
Pirates Blame Someone Else (9/15/1998)
Software Pirates Nailed (8/21/1998)
Pirates Get the Boot (6/30/1998)
EA and Cops Just Say No to Pirates (6/3/1998)
Calling All Pirates (2/4/1998)