After installing iTunes 9 I've noticed that my MacBook fans were getting pretty loud, so i've looked in Activity Monitor, and saw that iTunes while playing a regular mp3 is using around 30% of CPU. When I disabled the visual equalizer in now playing window it goes down to around 5-10% which is still too high for a simple task like playing an mp3. I don't think it was that high in iTunes 8. The problem occurs on both my machines, an older white MacBook, and a new unibody MacBook Pro, both on 10.6. I've also already experienced one crash with iTunes 9. Here's hoping for 9.0.1 soon.