I love this Starbucks in spite of myself. It's a bit grimy and crowded but because of it's unique location, poised at the tip of State St., it's inserted itself right into the center of Madison student life.
When I went to college at UW, there was a warm, gray-haired barista who would sometimes be the only human contact I'd have all day. I'd see her at 6am (This Starbuck is open the earliest of all the downtown coffee-shops) and her warmth would make my day. I came back to visit recently and she was still working! How nice that some things don't change.
Some advice:
Study upstairs it's comfy and quiet and has it's own bathrooms. Downstairs is more for socializing.
They have special deals around finals week
They are open ungodly early
They are a hub for the homeless population in Madison. Make of that what you will.
This location has the reliability of any Starbucks anywhere--an internet connection that doesn't cut in and out, cute spaces for reading, calming music, strong coffee, chewy rich bakery treats. Ideally I'd like to support local coffee shops but I come here because they just do it better than anyone else!