There are several Horno San Buenaventura locations in Seville and all of them offer the same great food and excellent value - and yes - the very best coffee in town. Also the only place in Seville I've come across that uses fresh milk (as opposed to UHT) in their coffee. The Horno has been my favourite breakfast bar for years. They also do good takeaway food and have a very good bakery.

Totally agree. Best breakfast in Seville. Just bear in mind that the waiters can be more unapproachable than God! Not all, but some.
Try the Cerveza Historico (not for breakfast obviously....although I don't know! I happen to like a couple after a long day wandering around the Barrio Santa Cruz). Also, have a yema, if you feel like being brave/foolhardy - crystallised egg-yolk made by local nuns. Why you would want to crystallise an egg-yolk defeats me utterly but they have and you can try one. Surprisingly, they taste of sugar and egg-yolk! The ideal gift for the not-so-popular relatives back home!
Nearby, there is also a very good Sevillano equivalent of our local chippie which does excellent roasted and salted almonds. Good for replacing salt lost in the summer heat.

Sad to say I have to change my opinion on this once excellent place. On a recent trip, January 2013, the food was vile and the service execrable. Very sad loss.