As I recently moved my mail server to a new cloud provider, I used this opportunity to check the mail statistics for 2011. All together I had
64.097 mails processed from which
42.469 where spam mails and
375 included viruses.
All together this makes 66.25% of spam. However, only 0,58% of processed mails included viruses, which is a quite surprisingly fact. Over the last year I encountered only two to five spam mails a day in my inbox, and I have not reported any false positive at all. In contrast, I pick up false positives in my GMX junk mailbox on a regular weekly base. For my personal mail server, I am using SpamAssassin with settings, I improved over two to three years as well as a set of various DNS blacklist.
Quite a part of the regular mails origin from various mailing lists and newsletters which leaves me with about 60 mails a day to process. A number to be definitely improved (i.e. reduced) for 2012.