Well this thread took an unlikely turn - didn't expect to see cars as a subject of discussion.
Best sound comes from a V12 (I miss my old Lamborghini!), next best from a straight six (sold my MGC but still have a BMW Z4MC), and after that maybe the rather blatting loud but unrefined V8 (though I still own them as well) and then the poor four cylinder (still own three of those - one makes 375 bhp out of a 2.0 - but the sound is always a bit inferior to the others mentioned.
This one (I drive it in summer) sounds decent as well, although a V6)