I too recommend Au Bon Pain in C1 if youre interested in soups, sandwiches and pastries.

What are people's take on Nathan's Hot Dogs also in C1? I always pass by it, but have yet to try it since I'm already salivating for a roast beef sandwich from ABP everytime I land at EWR.

In C3, Cafe Juan Valdez and Jamba Juice are good for snacks and drinks, but in terms of food, Famiglia Pizzeria is the only decent place there that doesn't break the bank on my usually limited travel budget! :-)