I thought the spam problem was pretty much solved a few years ago with the popularization of Bayesian filtering algorithms. I use email for the vast majority of my business communications and it works perfectly well.
When Google/Postini can't deliver my mail to my users I have a problem. When they can't deliver their own mail to their own users we all have a problem. But it's worse than that - any given recipient will be running a system with an unknown false positive rate, so email degenerates into a game of chance.