I upgraded to Snow Leopard as soon as I could and immediately felt there was a big slow down with lots of Spinning Beachballs, etc. Terminal showed between 5 and 12 stuck processes at all times and the whole system ran like a dog.
After a lot of digging around I solved the issue by getting off FileVault. I travel a lot and don’t want somebody to be able to get all my data when the inevitable happens and I lose my laptop. I’m not certain whether it’s my machine (I didn’t do a clean install for Snow Leopard) or 10.6(.1) itself. Either way, even if I created a new user with FileVault I saw stuck processes, without FileVault they are very rare.
Sharing with the world in case you too are in this boat.
PS: Yes, I did run Disk Utility and fix preferences both before & after install. SMARTD is showing no problems either.