There have been reports that the new iTunes v8 upgrade is crashing Vista machines. Some are seeing a BSOD, or an immediate reboot upon connection of an iPod to the Vista machine. I have been having problems too, no BSOD but iTunes stalls/crashes and the iPod is not recognized. If I let it sit for ten minutes, eventually iTunes responds and my iPod is recognized. That machine is running Vista Ultimate, so that may be why I'm not getting a complete fail, but it's hard to say.

Apple has released instructions on how to repair the problem. Here is a shortened version, but the entire document can be found here.

1. Disconnect your iPhone or iPod from Windows Vista.

2. Uninstall iTunes and Apple Mobile Device Support

* For Classic View
1. Choose Start > Control Panel > Programs and Features.
2. First select Apple Mobile Device Support, click Uninstall.
3. Select iTunes, click Uninstall.

* For Control Panel Home View
1. Choose Start > Control Panel > Programs > Uninstall a Program.
2. First select Apple Mobile Device Support, click Uninstall.
3. Select iTunes and click Uninstall.

3. Restart the computer.

4. Re-download and install the updated iTunes 8 installer from www.apple.com/itunes/download.
Important: Do not use the iTunes8Setup or iTunes864Setup file you previously downloaded.

I've tested this on one of my Vista machines and it does solve the issue. I will be testing the solution on my other Vista machine at home tonight.