Personally, I have been using GMAIL as my main email client, allowing gmail to access all of my POP accounts and utilizing the IMAP server, I can have all my mail synchronized on whichever email program I choose to use, and since I have a macbook in the mix of other PC computers now, it truly doesn't matter since GMAIL is a web-based email program I can always retrieve my email. GMAIL has, in my opinion, the best methods in handling the SPAM to the point where I'll make a quick glance through the hundred-plus email that it has found and then clicking one button removes it all permanently. It has been about 15 hours since I checked my mail due to traveling, as well as being the weekend, I had 605 spam messages, all of which were promptly deleted.
So when you get more then what you used to get what I suggest is first making sure you are up to date with your anti-spyware programs and do a full scan. Read my OPTIMIZING TIP as well as the many others available from the TIPS page, and be sure to have the latest in the anti-spyware programs by downloading it from my SOFTWARE/SUPPORT page.
What I do see most often on the various client computers I will be cleaning/updating/repairing, is the amount of JOKES people send from friends and relatives, all sent "incorrectly" as with a couple hundred of the email senders contact list in the "TO:" box instead of utilizing the "BCC:" You can and should learn THE CORRECT WAY TO SEND AND FORWARD EMAIL from my available tip. I do believe we will never completely win the battle of SPAM, but in order to have any sort of control over it, it must first come from within (ourselves) knowing the correct measures in order to avoid getting this in the first place!