Panther "stuttering freeze": An issue where the system becomes unresponsive, but the mouse can still move -- albeit in a jerky fashion. Commonalities among those experiencing the problem include iTunes running, and the presence of certain USB devices or drivers.
Trackpad: Cursor jumps erratically while typing: Cursors on PowerBooks and iBooks continue to move while typing even when "Ignore Trackpad while typing" option is on. Trackpads are so sensitive, it seems, that one user was even able to move the cursor via his trackpad through a 1" phone book.
Icons scrambled after restart/Finder re-launch: In some cases, icons on the desktop or elsewhere will be scattered in a random fashion after each restart, logout, or relaunch of the Finder. Deleting the invisible .DS_Store files in problematic folders using a tool like Cocktail generally resolves the issue.