For a great view of the city (especially at night) go to the top of the Eiffel Tower at Paris. It also offers a great vantage point for viewing the water show at the Bellagio.
My advice would be to do as many excursions as you can. They are a great way to get to know your group, and they are always good fun.
One of the most amazing places in the world! Best thing to do - GET LOST!