I think what I really love in a bike (retro or modern), and this is probably why I mentioned some of the things I don't like in the 'other' thread, is a
sense of purpose: this explains why I don't like obviously badly set-up bikes - all the bits are there but the sense of purpose is gone.
This also explains why, for example, I adore bikes like the Breezer Mk 1: they have a massive sense of purpose - it looks like it's ready to go and everything that's on it is there for a reason (still feel the need to learn to frame build at some point in my life and make myself one).
I really don't give a monkeys about everything being period correct, other than for the fact that those components might work better with a given frame (a=c heights, for example), and I really don't care about mixed groupsets. If it looks 'right' then that's good by me.
I love fresian cow paint jobs as well. They rule.
And did I mention purple anno as well? And purple anno. Then there's purple anno to consider, of course...