The beauty of FR has always been an interface common to all. But, if favored style sheets become common, seems to me like that will make it easier to radically alter the look and feel of the place. I can see it now, "Get your style sheets here - one special made to suit your personality."
I really do hope that I am dead wrong... 8^)
Seriously, I really do like the idea of a customizable Free Republic. The more gadgets that can be tweaked, the better, IMHO.
My job will be to hammer together an HTML guideline to coordinate HTML usage. Such as using <EM> to highlight, and <I> for italicizing. Or coming up with something different (like using a CLASS="hi" for highlighting.)