I was part of something similar once at the office, but we only picked names, no wish list was attached. So it was up to you what you give to the person.
About the element of surprise, that is both good and bad. You may get a nice gift, or something you don't like, but I think I would still go with not making a wish list.
Anyway, good luck and I hope you get the watch.
Thanks for sharing your experience. Before we had no wishlist, but through time we appreciate having a wishlist then. I am hoping for the watch but if it's not, it would still be ok.