Snow Leopard broke my favorite screen saver, WhiteCap (by Sound Spectrum). The WhiteCap app still works great with iTunes, but the screen saver is kaput. If anyone is interested, here's the official response I received this afternoon from Sound Spectrum:
"In updating all system applications and architecture with 64-bit code in this new operating system, Apple no longer supports the running of 32-bit screen saver modules. This unfortunately means that the WhiteCap screen saver, as well as almost every other third-party screen saver previously available for Mac OSX, is currently not compatible with Snow Leopard. Since the development time needed to provide compatibility in this environment is daunting, and since this development time is multiplied by the numerous other software developers affected by this situation, we have instead filed an engineering feature request with the Apple development team so that they may hopefully address 32-bit screen saver support in a future update to the Snow Leopard OS.
I apologize for the inconvenience, though we hope you understand that we cannot account for major changes such as this when a new operating system or media player is released, nor can we advertise or promise compatibility without knowing any new restrictions or requirements that may be implemented."