Potbelly Sandwiches might be the best sandwich on/near campus, even though it's a chain. (Silver Mine comes a close second on my list)
The staff is always friendly and your orders are prepared in a speedy manner. They often speed up the process by having you pay while your sandwich is going through the oven. The extra speed is appreciated.
When it comes to soda their machine distributes both Pepsi and Coke, something I don't recall seeing in too many places.
Their chocolate chip cookies are too die for.