I'm always looking for ways to tame my in-box. Maybe you are, too. After all, if your ability to make a living depends on your ability to find and manage information (including what passes through your in-box), you need all the help you can get in managing spam.
Earlier this summer, I started using a helpful in-box sorting tool that is rather appropriately named SaneBox. It sorts your mail into a very limited number of folders based on rules you determine. (I don't know about you, but I used to have about 100 mail folders--and I spent an insane amount of time setting up filters to route my mail to this older or that folder. SaneBox eliminates the need to do all that thinking and fiddling. You simply decide whether emails from a particular sender are top priority (in which case they should arrive in your regular in-box), whether they could be deferred to a later time (SaneLater), or whether you never need to hear from this person again (SaneBlackHole). There are a few other folders you can use (I use SaneNews for all my newsletters and press releases). But that's the basic idea. You do have to remember to take a peek in your non-priority folders (it's tempting to forget that they exist). But that was a major problem for me when I was filtering email into 100 different places. I forgot that they existed. I'm feeling a lot saner since I found SaneBox. Perhaps it will be the solution to your email woes, too. Cost: $7.50/month and up.
The second app I've started using is called AwayFind. I've only been using it for a few days, but I has already proven itself to be extremely valuable to me. AwayFind is an e-mail babysitter. It watches your e-mail for you so that you can go off and do something more productive (as opposed to checking your email every five minutes and surfing the Web to kill time while you're waiting for an all-important message to arrive). When that message does show up, AwayFind alerts you (via your choice of method: text message, iPhone app, or email). I've set it up to notify me by text message when my editors email me, so I can respond right away. It sure beats not noticing an important e-mail from an editor because it got buried in my in-box. Cost: $4.99 and up.