Pause during cutscenes
Sometimes, hitting Esc during cutscenes will pause the game - hitting it again will un-pause it. The sound is correctly paused and resumed as well, even mid-sentence.
Unfortunately, this doesn't always work.
Apparently, if you have patch 1.0.4.0 (Title Update 2) or above, the cutscenes pause if you ALT+TAB out of the game.
According to the changelog from this link. (click on "Click Here To Show More Patch Details").