I used to be in that situation (200-300 spam emails per day) until I started using snipped-for-privacy@privacy.net for 3-4 years as my posting address. I always included a valid 'readable by humans' address in my sig, so I could be contacted if necessary.
You'll note I've recently acquired a gmx account which is live and which I now use as a posting address. Thus far I haven't had any spam on that addie. Makes me wonder if the spammers have to some extent stopped using spambots to harvest email addies.
I've used MailWasher for some 5 years now, and it has the advantage that you can get a text-only look at emails and action them before downloading them to your pc. The prog has white and blacklists, and can also be linked to spam databases, so mail is quickly identified as spam without ever having the need to open it. The best bit though, once you've identified email as spam, it can be deleted automatically by MW from your ISP's server without ever having to download it to your pc.
As I also do some shopping on line, I can 'hold' legitimate emails on the server until the goods arrive, then delete them without actually downloading them also.
I probably get 10-30 spam emails per day, some days more than others. The only mail I download to my pc is mail I actually want to have on the pc.
The company who market MW have one or two other progs that are worth a look, B9 (Benign!), which can recognise and strip off possible harmful attachments, and First Alert, which is their own spam database.
All that, coupled with Panda Internet Security (not quite as resource hungry as Norton, although it does have a habit of updating itself which hogs all resources right when you're in the middle of doing something!), and I reckon my pc is pretty much secure from any outside interference. :-)