I'll always have love in my heart for the 23, because it was my first gun. I will also always love the 27, because it was such a joy to shoot.
As far as current favorite, though, I'm torn between my 29SF and the pure power of the 10mm and the 37, which is just a fantastic and accurate gun. I think if I really had to pick one I'd have to pick the 37, only because I'm finding the 10mm to be a little hard on my hands these days.