There’s a new feature that Frakes talks about called: VIP:
>We all have particular people—our family members, our boss, our bookie—whose messages are more important than others. While Mail in Lion let you use combinations of rules, labels, and mailboxes to make a particular person’s messages easier to identify or view, Mail in Mountain Lion adds a new feature that’s custom-made for such purposes: VIPs

I already do this by flagging email based on a rule, but this looks way better.

Posted by Ben Brooks