I try to keep all my music normalized. Most of the non-classical albums I have already seem to be normalized, although I think in some cases I have had to go back and re-rip with normalization.

For classical, normalization isn't enough because of the dynamic range, so I wrote a short program to compress out the extreme dynamics and make sure the entire track is as loud as possible. It works pretty well, although the background noise is much louder during the quiet passages, and some of the more dramatic parts of the music are washed out a bit because the extremes in volume are removed, causing some strange effects sometimes (although you still can easily hear the contrasts between "quiet" from "loud" parts). Purists would be horrified. But I definitely think it's worth it, because classical music is unlistenable in the car otherwise.. Half of it is inaudible and the other half is way too loud.

BTW I use musicmatch 4 to rip and encode at 128kbps.