El Mundo is a great study spot and is always packed with students (they go there like moths to a flame!) They have a wonderful list of drinks my recommendations are;
1) Hot Chocolate - if you're feeling adventurous get it with a raspberry shot
2) London Fog Latte
3) Italian Soda
Their salads and sandwiches are great - your standard fare.
warning: avoid the soups and the croissants they are disappointments.