I spent time in Spain last year, and if you want a cute seaside town which is totally Spanish visit Sitges! It is about a 1 hour train journey from Barcelona..
Stay at the Platador Hotel which is only 60Euro per night and has the most comfy beds! And serves up a delicious breakfast each day! It's opposite the beach and there are cute little bars and restaurants throughout the laneways and there are waves on the beach!
BUT...it's got a bit of a reputation for being the gay capital of Spain! Not that that matters! Lots of good looking men about!
And... I agree with mish! Don't go to costa del sol!!