Barcelona would be a good place to start. It's a relatively inexpensive trip, especially with the strong dollar now, it's pretty easy to navigate, etc.
If you have a smart phone, take it with you. For 20E you can buy a tourist sim chip from Vodafone that gives you 1GB of data and you can have access to GPS, Google Maps which includes Barcelona's mass transit system, etc.
Rome would be my second recommendation to start. Also very tourist friendly, easy to get around, it's very easy to find English speakers, etc.