The terms Clive suggests might well be exactly what the original poster was looking for. However, I just want to point out that they mean "collection" as in "the act or the hobby of collecting," not the actual collection of items that you keep in a desk drawer. If you just asked someone to define "philately" they would probably say "stamp collecting
isn't it "numismatics"? I guess, although a collector is called a 'numismatist'. Technically, I believe the hobby can also involve the collection of medals.