Best place to live in Barcelona and around?

Dear all,

We are planning to relocate to Barcelona with the family, and we're starting to look for apartment/house rentals. I wanted to turn to you for advice or any information/tips on what are the nice areas of the city to live in, or - what are the nice localities in the greater Barcelona area (by this I mean anything at up to 1-1.5 hours drive to Barcelona)? We're a family with two small kids, so I'm looking for a very child-friendly place: quiet and green, with good infrastructure and easy access to the city center, beaches etc.

Many thanks!
Olga