At Walsh Construction, we have a service that filters out our spam. This company is called mxlogic.
They really do a good job in my opinion. Since we switched over to using them, I am no longer worried about giving out my email address b/c I know that spam will most likely not reach my inbox.
Now, it looks like Microsoft is going to offer a similar service: http://www.microsoft.com/exchange/services/buy.mspx
I might want to look into this for some of my long lost email addresses.