I wonder where I can write to say I will no longer be buying CDs, not for me, not for gifts (and I bought a lot of them.)

They're also apparently suing people who were out of the country when the supposed infringement took place.
This is the problem with basing suits on IP addresses- most IPs are shared either across computers or, if fixed, by multiple users on one computer.

These poor folks are simply being exploited by the RIAA as warning signs to music downloaders. RIAA is obviously seeking to make these incidents as high-profile as possible in order to intimidate as many people as possible. It's unfortunate that the average person who gets hit with one of their letters, is understandably going to cower and submit, instead of calling for a lawyer, which is what they should do, if they have the resources and time.

The industry has been overpricing it;s product for years and getting away with it. CD's cost a nickel to press and sell for $16.99 or more. The rampant piracy is a direct result of their unabashed greed.