Our company provides ANR headsets for the Dash 8 (300 & 400).
I also bought me a pair of earplugs:
http://neuroth.at/cms/cms.php?pageName=190
(sorry - page is only in German, but you'll get what I mean).
Wearing them beneath the ANR headsets makes the cockpit a nice and quiet place (appart from the volume of the headset now being put to almost max.
)