We haven't seen too many Snow Leopard screenshots leak out, but it looks like a few more have finally surfaced, and they seem to show some interesting -- if minor -- interface enhancements. Most notably, Stacks now allows nested browsing, so if you click on a folder in the stack view, the old stack drops back and you can navigate the folder contents -- the old way just opened a Finder window. Other improvements include a Put Back menu item for accidentally-trashed items, a redesigned Keyboard Shortcuts prefpane that might encourage people to actually use it, and what looks like a welcome new installer option to only install printer drivers for printers that have been used with your machine. Tha