I've been going to Upper Crust even before I moved to Austin 13 years ago. I have a totally, crazy sweet tooth, so trust me when I tell you that this place has some of the absolute best baked goods in town. My all time favorites are their chocolate cupcakes with a cheesecake center. The bakery is a perfect place for a weekend morning. I love going there, getting one (or two if I'm being bad) pastry item, some coffee, and reading the paper next to the sunny window. Of course, that's assuming that there are any open tables when I get there. They stay pretty busy and for good reason. Parking can be a pain, but worth the effort. If you really don't want to fight the crowds, go during the afternoon when it slows down a little more.
I love Quack's! I've been going to them ever since they had the location on the drag. And during college, they nourished me with fresh, baked goods and coffee for 6 straight years. The employees are usually pretty nice and the place is always packed. However, they have so much seating available that you can almost always find some open seating. Here are some of the desserts that I really enjoy there: rosemary apple pie, coconut pie, salty oat cookie (sounds weird, but I guarantee you'll like it!), pecan snail danish, Italian cream cake, carrot cake, and the most kickass sugared cinnamon rolls I've ever had in my entire life!
This is one of my favorite bakeries everything is good. However, I found out from the staff that lots of food is thrown away if it doesn't sell -- I was shown huge bags full of edibles (I couldn't have fit them in the trunk of my car.) This is shameful, in other cities here in Texas, such food is packaged and delivered to "soup kitchens" so that it can be incorporated into meals. One kitchen said that they could use anything edible to create meals. I was disgusted that in Austin of all places that such an upscale business would throw away food that had been for sale only an hour earlier.