I don't mean to beat a dead horse, but all you Outlook/Outlook Express users should seriously consider what a previous poster said about Thunderbird.  Microsoft's email and browser programs are the target of every virus writer and hacker in the world.  Also, while it may not affect you right now, the underlying architecture of the program is really ugly and will consume your overall resources like no tomorrow.  Finally, Microsoft deliberately makes things difficult for people you write to, or receive from, who are using other email programs.