I would second Cocco Pazzo Cafe. My son has been spending a lot of time at Lurie (next to Northwestern) and we have brought him their Spaghetti AOP as a take out order, which he has really enjoyed. If you need to get away from the hospital scene for a bit, Cocco Pazzo provides a wonderfully quiet, peaceful respite. You can also call in take out orders at Gino's East, which is right next door to Lurie. Call ahead and you by-pass the lines of tourists. There is a convenient take out counter inside.
"I live on good soup, not on fine words." -Moliere