Anti-Spam recommendation

I searched through the archives and couldn't find any threads that address this topic.

I've just started a blog, and my spam comments already outnumber my legitimate ones. They never get published as I have moderating authority.

But, still, it's getting increasingly irritating to get excited over a new comment and then discover it's #!*# spam.

I've checked on many spam filters, and I haven't found one that suits me. I hate captcha because more times than not I can't decipher the words and have to keep clicking until one that's readable pops up. I don't want to put my visitors through that hassle.

Likewise, I'm not a fan of registration. One more hurdle to letting someone leave a comment.

I'd like to be able to prevent the spammers from ever getting through, thus saving me the trouble of deleting their bogus comments. I'm not sure if the "are you human?" box would work or not, since some of the spammers could indeed be human. But checking such a box is OK with me.

I'd love to hear what works for any bloggers with a similar mindset.

Thanks, Ben. I see use of the tool on Debs and Errol's site, but I don't see any links for downloading it. I did a search on "please prove you are not trying" and the only thing that popped up was their site.

Is that math question a plug-in? Do you know where I can find it?

An update to above: For anyone interested in BenBradley's very useful recommendation, here's a link for more information and a download: http://sw-guide.de/wordpress/plugins/math-comment-spam-protection/

I like the original file a lot better than Debs and Errol's implementation of it. It's very straightforward. It adds an extra field that you can place anywhere in your comment field and says: Spam protection: Sum of 9 + 9?

The link above also offers some other useful methods of combatting spam.

But I never would have found it without Ben's suggestion. So thanks again.