Since switching over to mac I've been using both a Quicksilver trigger, and right-clicking on the little padlock icon in the toolbar, to kick off my screensaver and lock my computer. After updating to Leopard I started to have a flickering screensaver, as if more than one screensaver was active at the same time. This has been bugging the heck out of me, but I've finally come across a solution on Mac OSX Hints (