I really like Lean Cuisine's Mac & Cheese -- on ly 280 calories for 10 ounces.
I try to keep on in the freezer at work for those days when a salad for lunch just won't cut it!
It is no where near as a fattening as say, regular Kraft Mac & Cheese which can be up to 400 cal/ 1 cup serving!
Is it good for you? Well, no, but that wasn't your question!
Other "comfort food" substitutes that I use include:
-- When I crave chocolate -- Chocolate pudding (fat free or sugar free) for about 100 cal/serving
-- When I crave salt -- I try a dill pickle (very salty!) or a can of spicy V-8 juice (salty, but no fat!)
-- when I crave ice cream I aim for the Skinny Cow Low Fat Ice Cream Sandwiches at 140 cal each, they keep me to a portion which is safer than if I opened a big carton of ice cream and hoped I'd only scoop out one serving!
Good luck in your pursuits of (low cal) pleasure!