Hi
I use to live in Nice for 8 years, and my father lives now in monaco, so i'm the one who can tell you where to go ;)
It depends of what you're looking for, but I think Monaco is a fabulous place to visit, it is very impressing, because of people, cars, casinos etc... You have also some great discos there such as "the Jimmy's" (35? for a single glass of alcohol
). I did not mentionned yet all the ladies how beautifull they are.. A lot of Italian girls, lot of beautifull strangers!! sometimes you'll have to pay, sometimes you won't ;)
Nice, Cannes and the other places around there are nice too, but this is not as much impressing than Monaco :P some greats disco's out there, check "Juan les pins" too !