Since filtering spam has only a temporary effect, how about developing a piece of software that works with all major e-mail clients, that when I tag a message as spam, it crawls back through the internet and throttles the sender in the nose.

You will make millions.

I am totally for that!

I have actually used Gmail for a good 7 years now. I do have to say they have a great spam detection system. I get maybe only 1-2 e-mails each day that are SPAM.

I'll second this, as a Gmail user since 2004, replacing my former primary email address on one of my domains.

Gmail's spam filters are very robust and accurate, detecting and sending to the Spam folder a couple of dozen messages a day. Very, very rarely does a spam message actually hit my inbox -- 2 or 3 a year, at most. On the other side, it's also rare that a legitimate message is tagged as spam. Don't know how they do it, but they do it very well.