A week isn't a whole lot of time to see more than a couple of highlights - though that's sadly the case with any country. Barcelona is certainly a wonderful city - it's on a very short list of Europe's best, in the opinion of many - but I'm not sure it's the best introduction to Spain. It has a very European feel to it, and it doesn't give you nearly the introduction to Spanish culture that the capital will. While many travelers don't take to Madrid from the start - Barcelona's far prettier on the surface - it's a better place to experience what the country's all about. Put differently: you know you're in Spain when you're in Madrid. In Barcelona, that's not always the case.
You can easily spend a few days getting to know the capital (El Prado, Reina Sofia and the Thyssen could very well take up two days themselves), not to mention its spectacular nightlife. You can do day-trips to Toledo, Avila and Segovia - all worth seeing - or head to Sevilla for a few days (though hardly time to do it justice). The bottom line is that as much as I love Barcelona, I think you'll get a better taste of Spain on your first visit by basing yourself in Madrid. But if you choose to ignore all that sage advice to head to Barcelona, you won't exactly be disappointed.
Buen viaje!
Chris
Travel better. Travel Gator.
www.travelgator.com