Spam avoidance is practice just like other security practices such as avoiding crack/warez/porn sites. For all round mail related issues,
About.com is, IMO, a good resource and I recommend visiting there first if you need some pieces of advice.
One of my family members used to have good amount of spam but almost all of them have gone after I let all his ISP mail forwarded to Gmail. I set
expurgate account for the address as well but it's Gmail that does all the job of cleaning up. Of course, I haven't changed the SMTP configuration at all and that person enjoys spam-free life without knowing what's going on behind. On the same PC, Avast! is working in silent mode.
As for spam avoidance, I forgot to mention that I use
trahmail. It has been bit stripped down but still works fine as temporary email addresses. For most suspicious senders, I use trashmail>spamgourmet>Gmail route.
