BRING AEROBIE!!! There was ONE place I accidentally found that roasted on site. It's next to the Sant Antoni market... I'll look up the addy & I have a pic of it somewhere. Unfortunately though, extraction skills left a lot to be desired
BUT was one of the best coffees we had while there.
Where in Barcelona are you staying? Also, across one of the corners of the market you can get some really, really lovely food... but then again, was only disappointed with one place of all the places where we ate during the trip
And yeah, Sagrada Familia is quite a sight to behold... seeing it in photos does not quite compare to when you're there looking at it straight out of the metro!! Keep an hour open for walking up/down Las Ramblas at most. If you like "fountains" then Plaça España in the evening around 21:30-22:30 for the show... lights/music... Of course, you do it quick by getting on the "city tour bus" which allows you to hop off & on and has about 20 tourist attractions stop off - there are 3 different routes tho.
I'll find my links and send them to you