Help with Spain Itinerary!

Just to point out:

<... We want to stay in southern Spain, preferably on the coast ...>, neither Barcelona nor València nor Majorca are in the South of Spain.

Barcelona is a city with a lot to offer and it's the capital of a region, Catalonia, the size of Maryland, with a very rich history and traditions and with an unusual variety of landscapes, from picturesque coastal towns to impressive mountain ranges (>10000ft), plenty of ancient cities (Roman, Visigoth, Medieval, etc). Although many visitors can only afford to spend a few nights in Barcelona, you could spend a whole month and still would have things to do / places to see. Have a look for inspiration: www.catalunya.com and www.infocatalonia.eu

We have been to spain and greece, an apple and orange in comparison; both are great fruits!
The beaches are not on a par w greece (whose are?).
16 nights provides a wonderful opportunity to sample the many cultures within spain. In broad brush terms we suggest:
Fly into Barcelona: 5 nights - research Montserrat, stiges, plus huge menu of traditional barc sites
Take the renfe ave train to madrid: 3 nights - research retireo parc, toledo and traditional madrid sites
Take the renfe ave train to seville: 4 nights - research flemenco, cordoba, ronda and traditional sevile sites
Take the train or bus to granada: 4 nights - research sierra nevada mountain villages, alhambra and typical granada sites
Fly out of granada on your return flight home.
Highly recommend you rent apts

There are dozens of variations to this trip. One of the best posters on spain provided the first response to your post.

Thank you Marbleskies and Enric! I appreciate your responses, but do neither of you recommend visiting Mallorca or Valencia? They seem to be well recommended with the typical "top ten places to go in Spain" type websites. Have either of you been there and are they worth visiting? We want to go to a few different cities and regions to get more of a taste of the diversity of Spain. Also, where are the best beaches on the Mediterranean-facing side of Spain?
Thanks again for taking the time to respond!

Australian beaches are pretty good, but once again it's apples and oranges (or perhaps mangoes and pineapples).
Logistics for a party of 4-6, to minimize travel, would see me favour a plan similar to Brad's - 4 locations for 4 nights each.
1 Seville (with day to Cordoba)
2 Granada (with day to Ronda & white hill towns)
3 Madrid
4 Barcelona
If you wish to include Paris (at the expense of Madrid ??) it's a TGV train ride from Barcelona - I would forget Marseille.
I have been to Valencia (but not yet to Mallorca) and would think for a first visit, with such a large party, that they should not be your focus on this trip.

Thanks so much djp_syd! I Ronda looks absolutely stunning and will definitely be added to our itinerary, probably with Seville and Granada. But we would rather drive ourselves than take the train (because it seems to take the same amount of time either way) and as we are starting in Barcelona, it would be a long drive to Granada. Which is a good city to stop at on the way? I see both Valencia (which you said isnt so great, why?) or Murica? We could also take the train o Madrid from Barcelona, which is only 2 hours, and then go from Madrid to Seville, and then possibly Malaga, bu the only potential problem with this is it would include less beach locations. Do you know what there is to do in these places? Sorry if these are stupid questions but I really appreciate your help!

Then perhaps something like this ...
3 nts Madrid http://www.ricksteves.com/europe/spain/madrid
3 nts Seville http://www.ricksteves.com/europe/spain/sevilla
With day trip to Cordoba http://www.ricksteves.com/europe/spain/cordoba
1 nt Ronda - dramatically overhanging and straddling a deep gorge, and home to Spain's oldest bullring.
3 nts Granada http://www.ricksteves.com/europe/spain/granada
2 nts Valencia - I never said Valencia was not great, just probably not the focus on a first visit.
4 nts Barcelona http://www.ricksteves.com/europe/spain/barcelona
If you wish to drive, I would pick up the rental car in Seville and drop it back in Barcelona.
Take the high speed AVE train from Madrid to Seville.
For the best sights in each place check on Steve's recommendations in the 'At a Glance' section of the above links.

Seville is a must see, but be aware that in July it is ridiculously hot. That might sway how long you spend there. Locals think you are crazy just walking around outside in July and August.