iTunes 7 is __terrible__ on my integrated VIA audio. The sound is distorted at best and there are many periods of "static" and "pops". It sounds like someone moved all of the EQ sliders to their max limit and then turned down the volume. Overdriven but not loud. This is very dissapointing because I like the new iTunes 7 GUI and I was looking forward to some of the new features and browsing the new areas of the store. But for now I am waiting for 7.0.1 before I do anything more with iTunes 7.
On the other hand, iTunes 6.0.5 works great. Sound quality is as good as Winamp. So the problem has something to do with iTunes 7, not my drivers or my OS (WinXP).
I'm still using iTunes 6.0.4 on my MacBookPro, I'm too scared to update to iTunes 7, even though it's a totally different platform.