Yes, I know- Snow Leopard is out! Best, fastest thing since sliced bread, as they say. "I'm gonna upgrade everything!", the irrational, futuristic you thinks.
Sadly, the voice of reason in the guise of RP has to step in and throw a bucket of cold water into the mix.
Here's the skinny in a Xinet world-
SL as server platform- not supported yet. Xinet's working hard at it, since new servers out of the factory are coming with it, but at this point, hang out and enjoy it on your laptop.
SL as client- here the news is better; it's working for the most part, but with a few caveats. There have been some AFP permissions errors, and you lose your contextual plugins, out of box. There's some workarounds to this that are in process, but be careful!
As always, a phased intro is key- try a few machines, run 'em through their paces, and see what you think.