Itunes is certainly not CD quality and conerting to WAV does not get you back there. As MG stated above, if you compress using a lossy scheme, you lose the data in the process.
This does raise another question about the state of audio. It's difficult to deny the popularity of Itunes, yet so many users seem to take no issue with paying more per song than the average CD for far less quality of a CD. Now true, there is the advantage of picking and choosing songs, convenience, etc, but I'm surprised this is largely a non-existent beef that people have.
I would never suggest that I have "golden ears" but I can tell there's a signficant difference between Itune copies and well done CD's. The detail or nuance seems to be missing much like the difference between watching Hi-Def vs standard TV. The movie or show is the same, but something's just missing... the detail. I seem to really notice the difference in the treble tones such as hi-hat work and other cymbal strikes. it just seemd to muddy together on the lossy compressed formats.