I was looking at the Rivendell web site this evening (hey, a girl can dream, right?) and saw their thoughts on bike sizing
I must admit that, despite being pretty well sold on a lot of their positions on various subjects, my handlebars on both bikes are slightly below the plane of my saddle height. That said, I knew I had to buy the touring bike rather than any of the other bikes I'd been considering when I got on it, rode 12 miles (which was near my limit at that point), and got off and my back felt better than it did when I got on, so I think they're right about the whole "it should feel right, you should not have to break in to the equipment" thing. But my lower back has been tetchy for years, and I have a lot of upper body strength for a woman, so this is probably an area where I am Not Like Other Cyclists.
...if you've never read the Rivendell web site, let me commend it to you as cyclist porn of a very particular kind. I flip through it sometimes when I can't ride. Their bikes don't meet my current needs and are, er, not inexpensive, but dang, they're pretty.