In select internal builds of vista a registry value was set so that holding down the Shift key would slow-mo all aero effects.
Just download the file and apply the registry value.
http://myfreefilehosting.com/f/891e020670_0.1MB

While this one works on Vista RTM, I actually miss other keys, like "Blur", "MagnificationPercent" and others, which really cannot be used today.

I ran the registry file, but am not sure what you're talking about. How do you enable this effect once the key is added? I held down shift, but nothing happened.

Well, I have Windows Vista Home Premium SP1, and I can slow down the effects with the shift key.
I remember I had to modify one key at the registry, can't remember which, but I googled it and it was maybe one of the first 5 sites.
It was a really easy thing to do.
Google something like "Slow Down Vista Effects", and you'll get it.

Here we go...