I'm sorry, but this is simply terrifying, and impossible to imagine any good turn based game to not have! There must be a noise when you press the End Turn button!!!!!!!!! Whether it is a crappy "Turn complete" to a harmonious chime!
It might not seem like a big deal, but it has many perks!
a) it makes it clear when a turn has been made, takes away the risk of not noticing two turns passing!

it sounds nice, and gives you a tiny sense of accomplishment
c) following from b, this possibly conditions your mind to think of that sound as a positive cue, and hence feel like working towards pressing the end turn button even more, just to hear the sound again!
d) it makes it feel like something has happened, instead of the silence and unnoticeable change in date!
Please, I beg you, add a chime option! Of course, it can't be an annoying chime, it has to be a comfortable chime!
(I was joking about the getting a zero thing, enjoying Gal Civ 2 at the moment)