First off is Cottonrake at 497 Great Western Road. They don't have much seating, only a bench around the window which probably seats about 12. I recommend trying their black pudding sausage rolls or a savoury tart, or choose from their selection of breads to takeaway.
Next is Kember and Jones at 134 Byres Road. It's a very busy little place so expect to queue for a table at lunchtime everyday. They have a huge selection of cakes and pastries as well as a breakfast and lunch menu. To takeaway they have a beautiful selection of breads and a deli counter, perfect for picnic items. Kember and Jones pride themselves on the best quality bread and coffee.