Nothing good that's not server-based or fee-based.
Hell, I'd just use rules to route everything through Gmail and let them do all the work.
Personally, I'm that -----] [----- far from setting up a little home email server myself. We use IMF at work for Exchange and it's nearly perfect. Actually, that gives me an idea...I wonder how good the Outlook 2003 standalone client spam filter is. Hmmm.