You can avoid paying toll for roads if you only use the backroads (no motorways). But it is slow, expect the driving time to go up significantly.
Toll for all of Switzerland is 40 SwissFranc, about 25 pounds. You get a sticker that is valid for the year in which you bought it. (The sticker for 2009 is valid from Dec 1st 2008 to Jan 31st 2010.) Toll in France depends upon distance travelled and road used. Some motorways in France were built by private investors, they recover the costs through tolls. You pay at the exit or at toll points. http://www.autoroutes.fr/ will help you calculate costs for tolls in France, www.viamichelin.com will help you calculate costs for petrol and plan your route.
I would suggest driving down to Marseilles via Paris. Most routeplanners will suggest going via Reims, but the difference is only a few miles. And while Reims is a nice city, it is not Paris. Stop in Paris for a day or two, rest and see the city a bit.
If you continue to Marseilles you can drive via Lyon and Avignon or via Clairmont-Ferrand and Montpellier. The route via Clairmont-Ferrand and Montpellier is toll-free, but takes about 130 kms and 4 hours longer because it goes through mountains (11 hours vs 7 hours, not including breaks).
Marseille can be nice and I also heard good things about Avignon. The Provence is generally a nice area to be in, just note that it can be pretty hot during the day. (So plan on getting up early and have any driving for the day done by 11 am.) See http://www.avignon-et-provence.com for more info on the Provence. I would recommend getting of the motorway here, travelling the backroads and hitting the small villages with the lavender fields.
Monaco is not particularly interesting, even if it is a must for you don't plan on spending more than a day there. It is just a spot on the Cote d'Azure where every centimeter of land is covered in concrete from upscale apartment blocks and posh houses. The F1 Grand Prix might be a reason to go there, otherwise pass it up.
BTW, the closer you get to Cannes, Nice and Monaco the higher the prices get for everything.
Near La Spezia: http://en.wikipedia.org/wiki/Cinque_Terre
Also: if you are going as far as Pisa, you might as well continue on to Florence and maybe Bologna. And going north, Lake Como and Lake Maggiore are worth checking out.
Travelling into Switzerland, consider driving over the Great St. Bernard Pass (Aosta - Martigny.) The historic road that winds over the pass is very scenic and very popular with motorcyclists and other people driving for leisure.
http://en.wikipedia.org/wiki/Great_St_Bernard_Pass
From Switzerland I would then drive back up through Germany, avoiding the toll-roads in France. There are some very nice spots along the Rhine Valley, Lake Constance, Koblenz, Heidelberg, Cologne. From many parts of Switzerland there is no big difference in distance whether you go via France or via Germany to London.
[ Edit: Edited on 16-May-2009, at 17:24 by t_maia ]