Just installed Snow Leopard. It is insanely fast. It will make it even extra annoying to use my turtle of a windows machine. I got a stop watch and timed startup and shutdown times. The startup time was 36.7 seconds to start-up and for processing to be done. The shutdown time is really amazing. It took only 5.2 seconds from the time I clicked shutdown until the computer was off. Applications are extremely fast now as well. I think Microsoft should do what Apple did here and make one release of Windows all about performance and reducing the size of the operating system versus adding a ton of features. My work computer takes over 15 minutes to startup and about 5 minutes to shutdown.