I've actually had to make this decision while living in SW Baltimore when a row a few doors down was on fire and we had to go; just in case.
Its amazing how fast you can:
-get a cat in a carrier
-unplug a desktop from everything
-find that box of your prized 80s punk 7" vinyl that you got at shows
-get the guns in their hard cases
-dig the firebox of documents, passport, etc out of the closet

I think all in under 3 minutes. Its great incentive when you look out your front door and flames are shooting 12 feet out your neighbors windows.