For longer than I care to admit I have been using my mouse, or track pad, to Quicklook Mail.app attachments. Well that stops today. If you have an e-mail with an attachment and want to Quicklook the item don't reach for the mouse, instead type the Command + Y key. This will Quicklook the attachment just like hitting the space bar does in finder. I hope apple looks at this and changes the Mail.app Quicklook in Snow leopard but for now this will help keep my fingers on the keyboard and off the mouse.