If you are going to Monaco then you should go to see the Trophee des Alpes, on top of the Turbie overlooking the city. You should also have dinner at the Chateau de la Chevre d'Or in Eze Village haute. The rack of lamb is the best ever, and if you ask nice the chef will make you a chocolate souffle for dessert.
The coolest thing to do is the tourist submarine out by the mole.
In Nice go to the old part of the city and go shopping. While close you might go to St Tropez...try La Pinede for a really expensive lunch.
Is my Pan Am ticket to the moon still good?