I would have to say flashy fawn, that's the color of our boxer, Nala (quite a biased vote!). I remember having to choose from brindle, fawn with black mask and two flashy fawn.
I can't exactly remember if we chose her mostly because of color or personality.
Anyway, if I have to get another one, my next choice will be fawn with black mask or reverse brindle.
If I really have 'THE CHOICE', I would collect all the colors!!!! Just love 'em!