Barcelona's Old City is one of the best areas for a romantic dinner and delicious food. Over the past few years, Barcelona and Spain on a whole have become a food lovers' haven with innovative, new restaurants springing up everywhere. Ciutat Vella, in particular, is a hub for tasty, experimental gastro tapas, Catalan and Mediterranean Fusion and international cuisine including Asian, Italian and even a few new kosher restaurants as well.
The Gothic Quarter and Born neighborhoods are ideal if you're looking for an intimate meal in an authentically Spanish/Catalan setting. Many of the restaurants are situated in old buildings, and even though most of them have been renovated, the charm of these historic buildings shines through thus providing for a truly romantic experience.
Ciutat Vella's Raval and Poble Sec neighborhoods also provide for some excellent dining experiences. If you're looking for rustic and African or Pakistani cuisine, the Raval has a large number of options. Poble Sec is home to three new Ferran Adria restaurants and is continuing to shine as one of Barcelona's fastest up and coming 'barrios'. If you're looking for something that's truly off the beaten path, check out some of the family-run diners and beautiful terraces in this area.