If it were me, I would have loved a pedicure. I have callouses all over my feet from running. Anyway that would've been the one thing I wanted in the spa more than anything. Massages, facials etc... are nice, but a pedicure you get a foot massage and your toes look pretty when you're done. And they are not super expensive. A lot of those spa experiences are so expensive! I mean if you have the extra money than go crazy. But we are on a budget so I am a big fan of small indulgences. I can't justifying spending a few hundred dollars to have my skin buffed down. I guess I want something to take home with me at the end, like pretty toe nails.
But I am sure whatever you choose she will love it, because its a really nice thought! Have fun!