Have you really and truly gone through all jewelry options? Hmm?
Trips are a fun idea, and there are almost limitless options. Have you considered a spa vacation? My sister recently sent my parental units to Hawaii on mileage awards, and I got them spa treatments at the resort they were staying at. They loved it.
Is she interested in art? Go to some openings at some galleries, pay careful attention to what she likes, and pick up some work by an artist she likes. I'm a huge sucker for this one, and some of the pieces I have are nice investments also.