Please implement the ability to filter based on more than on condition.
An example of when this would be useful: That friend/family member that always forwards the chain emails full of animated glittery butterflies/rainbows/puppies with the "forward this to 20 people and you'll get your wish" taglines.
I would like to be able to set up a filter something like this:
If From firstname.lastname@example.org Subject contains Fwd: Fwd: Fwd: then send message to Spam.
This means that legitimate emails from that person with real information in them will not be blocked, and multi-forwarded messages from other people will not be blocked.