After installing Snow Leopard the eject button in the Finder for external hard disks occasionally fails. If you click eject and nothing happens (repeatedly) the solution is to right-click on the drive and choose the "Eject" menu entry. This will just about always eject the disk (unless it's still spinning up and Finder is waiting for the control signal to kick in). You would think the selectors for the widget and menu item are the same, but they mustn't be. I thought I'd mention it here in case anyone else had the problem.