There is an infringement case going on right now called Atlantic v. Howell. The RIAA is arguing that ripping a CD you own to your hard disk is infringement. This is not just a witness statement, this is part of their arguments in the case.
It is undisputed that Defendant possessed unauthorized copies of Plaintiffs’ copyrighted sound recordings on his computer. ... Once Defendant converted Plaintiffs’ recording into the compressed .mp3 format and they are in his shared folder, they are no longer the authorized copies distributed by Plaintiffs.
Curiously enough, back when suing Grokster, they said the opposite:
The record companies, my clients, have said, for some time now, and it's been on their Website for some time now, that it's perfectly lawful to take a CD that you've purchased, upload it onto your computer, put it onto your iPod. There is a very, very significant lawful commercial use for that device, going forward.
the legal brief:
MGM v. Grokster:
Some people here were panicked by the Jammie Thomas case. Well now
is the time to panic. This is the case they will use to try to make ripping your own CD illegal.
I don't think it will work, but it looks like they will try.