I love it when a man buys me perfume (not other beauty products like makeup though). If you know what she wears and like it, why not buy her a gift set or other products with the scent. Or, ask the perfume countergirl to suggest something with a similar scent (e.g. a newly released floral or musk) and take a chance and buy it. However, do not skimp and buy her cheap perfume - ever. I recommend a classic French parfum, and I am partial to the classics like First by Van Cleef and Chanel 5. There is a reason these perfumes are a bit pricey and have stood the test of time - they smell good.
Maybe even buy her a few small bottles of good perfume... a small sampler so she may experiment. This is good and only $50 -
http://www.neimanmarcus.com/store/ca...827cat18130745