I took some visitors to Schillthorn when they came (we stayed in Interlaken) and it was incredible. We basically went to Interlaken without a proper plan (waiting to see weather) - when we woke up and it was a clear blue sky we decided on the Schillthorn
you take 4 different cable cars to get up there, and the views are breath taking, I really recommend it. The trip is expensive but the restaurant at the top isn't, and has a James Bond museum.
Also, the Creux du Van is really nice and I've been there often because I live in Neuchatel. I also love Lucerne and Lausanne...
If you go to Creux du Van and like watches, then you can also go to the Musee d'horologie in la chaux du fonds - really nice watch / clock museum!
I'm making my first trip to Zermatt in a couple of weeks
All the best