If she likes watches, get her a really nice one. You can get very nice ones at costco for a couple hundred bucks. They are very dressy, and a nice accessory to any outfit, casual or formal.
For your 100-500 range you could also get her a very nice set of diamond earrings or necklace! Watch, earrings, necklace, any of those I would love to get!
Oh and if you take one of my ideas... I good without the picture
