Do you have a Trader Joes near you? Their cheese prices are very good.
I would go with a
soft cheese: brie or camembert, w/ high creme content
blue cheese: Rosenborg Danish bleu (get the extra-creamy if you can)
a nice gruyere (Do not get the processed type)
an aged cheddar
These are the basics but feel free to experiment with some chevre, a morbier or some other lovely French cheeses. A little goes a long way with the more exotic types.
re: babette feasts
You made my day. Easy to remember and good advice, too.
I pretty much stick to that structure myself, though I also like to pick choices all from the same country, if I can. I also try to balance stinky and mild, so that both the flavor-phobes and the stinky-cheese-lovers will be happy. And I generally avoid most cheeses that have been adulterated - I mean flavored - with herbs and things. Actually, that can be fine - for a fresh cheese, for example - so my rule is actually, ONE "flavored" cheese at most.
My new favorite plate includes Epoisse, Shropshire, Ossau-Iraty and a trapezoid-shaped moldy French goat cheese (can't recall the name) that comes in a tiny, adorable box. Maybe throw in a super creamy brie for the folks who aren't looking for a taste sensation.
Should be under $40 until you throw in some yummy pears and apples to eat with the cheese.