Kelly for me. I have yet to fall for a Birkin.
To me the Kelly is just the most beautiful bag on earth. I like it in every size, style, color, skin, sellier, retourne. I haven't seen one I didn't like, except maybe one very strange looking tri-color.
At first I felt it was a little bit of work to get in and out of, but now that I've been using one everyday for a while, it really isn't that hard.