Somehow, I think anything we could suggest would be lame because we really don't know her like you do. After this many years, I'm sure it's not easy to do something unique without repeating.
My best advice to you is to not only think of things that she likes, but to think of things that she doesn't like and do something to "fix" them. Besides you, what does she complain about?
Is she tired of her clothes? Buy her a shopping spree. You know, that kind of thing. I mean, you need to supplement the necessity with the nice stuff like the earrings.
Do you ever get dressed up and go out? Dinner, dancing, a show, a night in the city? C'mon, don't just copy Steve's presents to his wife.