No matter what platform you're on, unless your ISP uses spam filters, the junk ends up in your mailbox.
Whether you're using a Mac or DOS or BEOS or Windows doesn't really matter. Most OS mail clients whether commercial, shareware or freeware, can be set up to toss stuff into the trashcan. As your rules learn or you refine your filters the more effective it gets. But you still have to sit for ages while the cr@p is downloaded (most of the world doesn't have broadband - surprise!)
Until the deluge is stemmed, the answer lies either with ISPs installing spam filters or a preview app. like Mailwasher which allows you to delete garbage directly off the server before downloading.
With respect to PPRuNe Towers and the Mac brigade (and no UNIX-based OS can be really bad) to imply that if the world ran on OSX we wouldn't have spam is specious to say the least.
Why don't I have a Mac? Well, the hardware is too dam#ed expensive and my choice of apps., excellent as they are, is too restricted. And compared to Windows/Linux, so is the freeware/shareware....
Maybe that's why I'm migrating to Linux (Suse 9.0, I love it)
Mac (Registered Linux User #302442)