A Better Signature Generator
I just discovered Signature Profiler, which is a great plugin for Mail.app (works on Leopard and Tiger) for creating signatures in Mail.app. Finally, I can get rid of the painfully hackish python (!!) plugin I was maintaining, which is good since it apparently didn't work in Leopard anyway. I never could figure out how to make it provide the signatures without a leading space on each line, which was pretty annoying.
This plugin provides plenty of nice options for managing signatures, but the main thing I wanted was to be able to include the output from my long-standing signature generation script (which largely just pulls a random file from a directory of the quotes I've collected over the years).
I also took the opportunity to trim my signature list; some of the quotes were funny in 1997 but not so much now.