Not to pile on, but it's nice to know I'm not the only one with the horribly slow import problems. It's too bad this thread ended with no real resolution -- was there one on some other thread I've missed?
It's not just a problem on the Mac version -- I have it on a Windows 7 install as well.
It doesn't seem to be a pure code problem. I have two notebooks with the same 10.4.0.80 release. One imports normally (still not blazing, but reasonable). The other is horribly slow (about 5 minutes per typical album). There must be some condition that kicks it into the slow import state. I've tried the home sharing and Genius suggestions, but the one is still slow.
Unfortunately, the slow one is the new notebook that I just went through the hassle of making my primary sync computer for my iPhone (BTW, it is just stupid how hard it is to change the primary sync computer for an iPhone -- really guys). I've got 13,400+ songs across 1280+ albums. At 5 minutes per album, it seems like it will take 4 and a half days to finish importing them all. Ugh!
I don't know whether Apple really doesn't care and doesn't want to invest in iTunes, or what, but it would be nice to take some of that huge hoard of cash they have and invest in some serious QA and expert multi-threaded developers to fix this thing once and for all. It's just plain stupid that importing takes so long, and even stupider yet that it locks up iTunes and makes the UI completely unusable while it's off doing whatever it's doing.