Just upgraded my Mac book pro to Snow Leopard Mac OS X 1.6 and ran into the following issues:

1. Adium doesn't work anymore with ssl handshake. It keep trying to connect but fails.
   
   • "Adium 1.4b9 SSL Handshake fails for Jabber under OS X 10.6"
   • No fix yet.
2. Open Office didn't want to start anymore and needed to be removed and installed.
   • Fixed by reinstalling Open Office from here
3. Cyberduck FTP client isn't working properly with Snow Leopard. A Beta version is available but it was still acting funny.
4. Copying files to my Solaris CIFS file server give error 36 messages.
   • Many reports on this on the Apple fora such as here