Forgive me if this has been brought up before, but will KMail ever have address book filtering? This is a feature I have found very useful in other non-Linux email programs. Another wish-list item of lesser importance would be the ability to scan a header for a long list of words (longer than the current filter system allows). A user could then scan for a variety of familiar spam words: viagra, satellite, mortgage, hurry, enlarge, etc.
I am running SuSE 8.2 with that Godsend application Synaptic. This is the longest I have ever kept Linux on a machine and actually plan to keep it around for a while.