Well currently I get about 1000 - 2000 email a day with roughly half of them being spam on any given day. I also build email servers for the city and a few other buiness's here in my local town. I currently have mine setup with spam and virus filtering. This then is filtered using maildrop into maildir type mail folders. I perfer maildir for the extra security and also the ease of using quotas. At any rate I use both imap and maildir. With Imap I can check the server and see what spam and virii have been collected. When I know that no spam is in my main inbox then I download through pop so the email can be searched easily and used for reference later. I currently have about 500,000 emails or so and they take up about 5 gig's of space. These I can access and search easily through kmail my email program.