thwart spam bots

I have been told that some people have "harvestor" bots that scour the web looking for email addresses to spam. I assume this to be true. However, what's the best prevention method on this? Use a javascript to join the username and domain? Use simple HTML code markup to disguise the @ symbol within the source? I'm interested in everyone's solution to this problem (other than making Spam illegal, or very costly).