Help me plan my trip to Spain

I’m going to be in Spain for about 2-3 weeks at the end of April and the beginning of May.

Spain is one of those countries that is packed full of things to see. It has the second largest number of UNESCO World Heritage Sites after Italy at 41.

I’ve never been to Spain before so I have no idea what to see or what I should make a priority.

I need your help.

Give me your top suggestions for what I should see/do in Spain. I know for sure I’ll be in Valencia and Madrid. Other than that, I have no other itinerary. If there are any events or happenings in Spain while I’ll be there, that would be nice to know as well.

Try also to think of places that will yield some great photographs.

Also, Robert Cole has a poll up on his travel industry blog on who the most trusted travel authority is online. Take a second to take the poll (yes, I’m on it).