Others were less concerned with the whole thing. Reader djones, for instance, felt differently: "I don't think it would be good to be 100% consistent across the board...you need some sort of visual indication of which application you're in. It doesn't need to scream it, but the subtle variations in Apple's first party apps are enough to tell you that they're a family, but you won't mistake one for the other."
I recalled this discussion earlier this afternoon when I saw a link to Uno at What Do I Know. Uno is a theme for Mac OS X that gives every single, solitary window and menu bar the exact same look (even the Dock's widget bar). Lach, this one is for you. djones, steer clear. Everyone else, make your choice. UNO is free (I could not find system requirements).