Working outfit

The title above has two meanings; I want an outfit for tomorrow that I can work in, and I want an outfit that is working to work in.

What is the proper thing to wear really on the first day of the job? I want to be rather stylish because it's a rather stylish boutique, but I don't want to overdo it. On the other hand I don't want to "underdo" it either, and at the same time I want to be me and not pretend to be someone else. So what should I wear?

I thought of my black pants with stripes, looking something like these, but I've got no idea what kind of top I should wear. Hm... Have to work harder on that one while I brush my teeth.

Now I really have to start getting into bed!

The picture is coming from Banana Republic.