On a related topic, the ability to import and export blocked/allowed email addresses and domains would be very helpful.
(To put some peer pressure on you) I find that I am using Outlook Junk Mail (Outlook --> Actions --> Junk Email) services because it has the ability to import and export lists.
I currently use NIS 2010 on a laptop and a desktop. If I don't use my laptop for a couple weeks, I get a massive list of spam emails that would otherwise have been caught if I could have just leveraged the spam filtering that I had setup on the desktop. Instead, I need to go through the long list of emails and duplicate the work that I have already done for the other machine...
With outlook, I have a workaround (nudge nudge...)