Rule number 1: never post your email address online. Anti-spam strategies, such as removing the link, rendering the address as a graphic or enclosing it into a PDF file, are all subject to fail. The best strategy is just to never expose it.
Contact forms are most useful in giving contact access to email without exposing the address. However, be aware that spam bots are adept at filling out forms and spamming you anyway, so you’ll need to take measures to prevent automatic submissions, such as a Captcha challenge.
Need drives the market, and the ever-increasing level of spam and viral infections on the Internet have given rise to a whole industry of mail filtering companies. The idea is to introduce DNS records into your system that routes your email into their servers, and their servers feed it back to you all filtered and clean.
Most notably, Google Postini is offering a very cheap service to individuals and small companies. However, this service comes with the typical level of Google support: nil.
Symantec and many other companies host solutions similar, if not identical to Google, which are geared more toward larger businesses and enterprise-level solutions. They cost more, but in a volume purchase, you get your money's worth.