The last one is pretty interesting -- the look she has, the lighting you've used -- works well! I might not have wanted it cropped as tightly, but for me this is your strongest shot. Nice job!
#2 and #4 would be my favorites in this set ... #4 might be nice in portrait format too, keeping the 'Chicago' logo on the right, moving her out of the center to the left - showing more of the shoulder and shirt. #3 effect is too 'obvious', if you know what I mean.
