We will be travelling along the southern coastline of Spain & France
during the last 2 weeks of May - starting in Madrid to Barcelnona to
Marseille to Monaco, and finishing in Milan, Italy (with some night
stop overs in between). Would like to know 1) what are the key sites
that we should not miss (we are not entirely interested in only
religious, historical or geographical sites to see - we love it all),
and 2) where are the most reasonable places to stay (best combination
of service and price)? Thanks.

I believe you'll get a much better answer if you increase your price
considerably. A fee of $3.75 (the Researcher's share of your current
price) might justify fifteen or twenty minutes of work. You are asking
two questions, each of which is likely to take quite a bit of time and
effort to research.

We drove round trip from Cannes France to Barcelona. One of the things
we really enjoyed was taking a slight detour and driving to Andora.
you go through the Pyranes Mountains and it is jsut very very pretty.
Picture post card pretty with a lot of green grass and cows grazing.

Have you worked on your trip using www.Mappy.com
Mappy is like MapQuest, but for Europe. In Mappy for Place they mean
City. Their travel times are very very accurate. After you have
reqested an itinerary or a map on the lower left of the webpage your
map will appear, if you click on the little icons above the map I
think it is the one one with Hotels, you will get a nice big map that
you can zoom in and zoom out on. Very very handy :)

I'll share my method of selecting hotels. I like www.Priceline.com If
you are willing to commit to specific days per city in advance. If you
want to be more flexible you can use my "Ask the Taximan" method. In
any city find a taxi and ask for hotel accomodations. If your main
objective is price tell the taxi driver that, or that you want a nice
place etc. Since you will be going through several countries with
different languages you might just want to use Google Langauge Tools
and write in English and have the Google Tranlating option translate
your English into the other languages, Your request might say "Can you
please help direct me to find a nice hotel for a low price? Thank
You."

Here is another alternative - How about taking a local cruise for part
of your trip. The French Riveria is going to be pricy (I know I own in
Cannes!)take a look at Easy Cruise a part of Easy Jet.
http://www.easycruise.com/Booking/ECRUBookLegs.asp?SD=39378231020060405054026&Type=One
I have never taken one of their cruises, but I see their ships out in
the bay in Cannes.

Using Mappy I think you might see that you are being a bit aggressive
in your itinerary. Are you flying into and out of Madrid? When you get
to France it is very easy to use public transportation, trains and
busses. You'll just miss the Film Festival in Cannes which ends on May
23rd.

In and around Madrid: Town of Avila near Madrid is a cool place to
visit if you like old caste towns. See article and info at:

http://www.seetheglobe.com/modules/wfreviews/singlefile.php?cid=19&lid=200

Also, take a look at Alastair Sawday's "Special places to stay" 
http://www.specialplacestostay.com/