My favorite places in the South: Verdon Gorge, Caracassone, Nice, Pont du Gard
I was unimpressed with both Nimes and Avignon - I expected so much more. I thought Marseille was just dirty and lacked the charm of other Cote d'Azur towns. That said, La Cour d'Honneur is a restaurant in Avignon with amazing blueberry cheesecake (the food was good, but not great), and with 10-14 days, you can see a lot, so why not.
Spending a day in Monaco is fun as well, just to go yacht spotting. Last time we were there, we saw four of the world's ten biggest yachts driving between Cannes and Monaco. Kinda cool. And I would recommend taking the drive along the coast between Cannes to the Italian border, it's beautiful. I am always amazed at how spotless Monaco is.
There is also a great little crepe restaurant in a tiny village called Rougon, which is a cool place in and of itself. A great view down the canyon while you eat, and you get to watch the vultures soar over the cliffs.
There is also a delicious al fresco restaurant in the town square of Aiguines, which I am willing to go out of the way to eat at.
Another interesting place to visit is the Rhone American Cemetery at Draguignan. One of the smaller and often missed WWII cemeteries, but recalls an often forgotten part of the war and the invasion of southern France. Very well taken care of. We spent the 4th of July there a couple of years ago.