Meet the tristate checkbox:
= Ignore term
= Include term
= Exclude term
They aren't terribly useful for scalar fields (publisher type, distribution type, release status, etc), but for bitfields (classification and category) you can now do much more powerful queries -- for example, searching for albums categorized as "animation" but not "game", or classified as "arrangement" but not "vocal".
Tristate checkboxes require Javascript to work; however, even without it you'll still get the old checkboxes with the usual functionality.