Apple have released a keyboard fix for MacBooks and MacBook Pros to fix the annoying “Forgetting I have an internal keyboard” bug:
This update addresses a responsiveness issue on MacBook and MacBook Pro notebook computers. Some MacBook and MacBook Pro systems may occasionally experience a temporary suspension of keyboard input which can last a minute or longer. The Mac OS X 10.5.1 update is required before installing the MacBook, MacBook Pro Software Update 1.1.
By “responsiveness issue” they mean you can’t type anything, or the command keys you’re holding down in your App (ie the Finder) go unnoticed when you click/drag.