i say that if you would buy only one cheese, Hoffman's x-sharp cheddar sliced up from the deli (it comes in blocks, too) would be a good bet. it has a nice sharp flavor, is great on sandwiches, for just snacking on plain, or for a cheeseburger, in a white sauce for a cheese sauce, in macaroni and cheese, added to potatoes, etc. and it's relatively cheap. in retrospect, at least.
bleu cheeses are good, too. they add a salty tang to lots of things, are good in salads, melted into dishes, great just for snacking, in salad dressings, on lamb chops and burgers and steaks, on and on. Saga makes one that goes for only $5 per wedge and it is so creamy and balanced. i love it. but i use all kinds of varieties of blue cheeses with success. bleu cheese can add a lot to a dish, and if it's melted, even those who proclaim to despise the stuff always seem to love the food. as long as they don't know it's in there. baffling.
excellent cheese.