Leighton Meester showed up to the Gotham Awards in a Thom Browne suit and honestly, she killed it. She looked sexy and effortless and cool. She softened the menswear-inspired outfit with feminine make-up, flowy hair and Faragamo heels, which might be why it worked like gang busters.
I tend to think women in suits look great. Of course, there are the occasional failures (lots of those ahead) but when it works, does it ever work.