I am in the crowd who does think this is important. Sure, once you get into a certain level of vehicle, it's expected that the thing is very quiet, but that's not always true when you're looking at more affordable stuff.
For example, I would want to live with a current Mazda 3 or Subaru Impreza because the road noise on the highway in both of those cars gets annoying during my 1-1.5 hour commutes. A Civic, Cruze, Focus and even the Elantra are much better from a noise standpoint.
Because it matters to me, as a driver, I mention cabin noise in just about every review I write.