Over the last few years, I've bought Tom Ford Black Orchid (snagged a bottle in New York the day it came out), Chanel No. 19 EdP, Montale Rose Attar and a vintage bottle of Je Reviens for my wife. She liked all of them. I have a pretty good idea of what she likes and doesn't like, so I felt confident buying them. On the other hand, I got her a bottle of Jicky a while ago and she isn't a 100% sold on it.
Lolita lempicka by lolita lempicka, dune by dior, hypnotic poison by dior, angel by mugler
All are easy to find and are masterpieces in my opinion.
Or, just do what i do, go to the nearest departent store, start sniffing and buy whatever you would like to smell on your wife.