I'll second the grilled cheese and tomato soup - sharp cheddar is the best.
I also like taking a toasted english muffin,putting sliced tomato on it, and then topping with whatever cheese you prefer. Put it under the broiler for a minute or so until the cheese get brown and bubbly.
Welsh rabbit is delicious and easy (stouffers makes a decent one, but you'll need to add a little beer to it. Creamed chipped beef over toast is also yummy, but fattening.