QuickTime 1.6 bugs are popping up all over. Jon Pugh <email@example.com> reported on Info-Mac that he isolated a conflict between QuickTime 1.6 and Now Toolbox 4.0.1p that caused problems when resolving an alias that mounts a network volume. In addition, two companies that I beta test for have mentioned that QuickTime 1.6 conflicts with the latest betas of their software (and no, I'm not going to say who since it's not shipping software). Beware.
Mac OS X Services in Snow Leopard
Mac OS X Services let one application supply its powers to another; for example, a Grab service helps TextEdit paste a screenshot into a document. Most users either don't know that Services exist, because they're in an obscure hierarchical menu (ApplicationName > Services), or they mostly don't use them because there are so many of them.
Snow Leopard makes it easier for the uninitiated to utilize this feature; only services appropriate to the current context appear. And in addition to the hierarchical menu, services are discoverable as custom contextual menu items - Control-click in a TextEdit document to access the Grab service, for instance.
In addition, the revamped Keyboard preference pane lets you manage services for the first time ever. You can enable and disable them, and even change their keyboard shortcuts.