Maybe set an auto-responder telling people how to contact you instead of by email? Or reject at the SMTP level with such a message (e.g. example with postfix). That way you can tell people who might try to contact you by email how better to reach you.

If you still want to receive email, I recommend greylisting, I have found that to greatly reduce spam I receive. Also using some blocklists helps (I use dnsbl.sorbs.net, bl.spamcop.net and cbl.abuseat.org)