Spain - Need to fill 5 days from Seville/Granada

That's easy. For Spain, I'd rent a car and spend a few days hitting the white hill towns - Arcos and Ronda for sure, maybe a couple others. The other obvious place you have missed (I think) is Cordoba. It's on the high-speed rail line, and doesn't really require more than half a day, but the mezquita is an incredible place, well worth seeing on any trip to that part of Spain. If you prefer Portugal, you could spend a few days either going south, to the Algarve (rent a car in Lisbon) or north to Porto and elsewhere.

No shortage of great paces to bolt on.

I'd have to agree with Maggie. Cordoba is a beautiful city and has much to offer if you have never been there. Also, I would recommend going to Segovia. It has the most impressive Roman aqueduct and beautiful shops and not mention great food! Anywhere in Spain is worth seeing, but these would have to be some of my favorite places! Enjoy yourself!!

How about Cordoba? Or Malaga? If you have a car, you could drive along the coast up to Barcelona.
If not, then the buses are good in Spain (and maybe the train too, but I've only been on a couple of them). Alternatively, look at flying- Ryanair have lots of internal flights in Spain.
Alternatively, maybe you could go to the South of France.
Whatever you decide, have fun, and let us know where you end up!

Granada was one of my favorite cities in Spain--you might add a night or two to Granada.

It might be backtracking a bit but the southern coast of Portugal is beautiful--Salema can be reached from Seville by bus.

I also like Maggie's idea about visiting southern France.

Granada is a wonderful city, I would definitely add another night there. The Alhambra and it's gardens are magnificent and so is the Albayzin area. See a Flamenco show in the caves.

I flew from Granada airport to Barcelona-Girona airport on Ryan air for a rediculously cheap fare (like 25 euros per person). From there we took a bus (Frog Bus), also very cheap, for an hour and a half drive over the border into southern France.

I would add Cordoba and then Valencia. Then when in Barcelona, you could go to Figueres, for the wacky Dali museum.

Look into a few days in Morocco -- it's cheap, close, and interesting as all get out. Fez would probably be my choice rather than Marrakesh.