One thing to bear in mind when using the various snow javascripts is that you should keep an eye on the effect is has on CPU usage consumption of your browser.
In nearly most cases (of those examples listed so far, too) my firefox.exe jumps from mere idle usage to 99% CPU use when the java scripted snow is enabled.
You may be slowing your site down for many visitors, or cause their computers to slow down while they are doing other things with your site open. This is the main reason why I chose not to use snow effects on my own site after I had complaints about the site performing poorly on users machines.
Oh well
