How can I get Snow Leopard to properly reconnect to my Windows network drives after it goes to sleep?
This is a known issue, and has no current hotfix or resolution.  The problem is in the samba implementation.

The only thing I can think of doing is writing a script to umount your samba just before sleep, and mounting right after sleep.  (Nobody has done this yet)

Most educated source on the problem I could find:
https://superuser.com/questions/144327/mac-os-cant-connect-to-smb-shares-after-sleep