Apple just released an update to iTunes with version 10.1.1 which apparently fixes some issues with syncing and unexpected crashes. I personally never experienced this issue but I guess it was a problem for some of you.
iTunes 10.1.1 is safe for jailbreakers and unlockers!
• Addresses an issue where some music videos may not play on Macs equipped with NVIDIA GeForce 9400 or 9600 graphics.
• Resolves an issue where iTunes may unexpectedly quit when deleting a playlist that has the iTunes Sidebar showing.
• Fixes a problem where iTunes may unexpectedly quit when connecting an iPod to a Mac equipped with a PowerPC processor.
• Addresses an issue where some music videos may not sync to an iPod, iPhone, or iPad.