There is a possible fix for certain issues in iTunes 10 involving re-installing iTunes 10 with this installation procedure at http://reviews.cnet.com/8301-13727_7-20017359-263.html.
Right now I'm concerned about how well iTunes 10 will work with the new Apple TV. As soon as I get my hands on a new Apple TV, I will do thorough testing and shake-down of the new Apple TV and iTunes 10 streaming system along with testing everything else in iTunes 10.
I will bring my testing results here at the Blog and on my JohnAtMacMobile twitter also. Stay Tuned.