If you've ever been in the market for drill bits, you know that there's a staggering selection available for sale, something for everyone depending on what you need to do and how much you want to spend. And while I have no intention of enumerating all of the specialty bits available for specific purposes, knowing a little about what the drill bits themselves are made of can get you a long way towards making your final choice.
Steel: At the low end of the quality (and price) spectrum, steel bits are the softest, will wear down most quickly and will heat up sooner under normal use. Steel bits are really only suitable for light work with softwoods.
High Speed Steel: Probably the most popular choice for the weekend handyman, high speed steel bits (look for the HS or HSS stamp) are a good compromise between price and durability. They are particularly suited to working with woods and plastics, although some are produced for metal working.
Titanium Coated: My personal choice, titanium coated bits cost more than the high speed steel, but the titanium coating is harder and the bits will stay sharper longer. If your need is not immediate and you can wait for a set to go on sale, I recommend these as the way to go.
Carbide Tipped: Carbide tipped bits are better suited to industrial applications, since they are able to successfully dissipate heat at incredibly high speeds. They are extremely hard, but are also brittle and can chip if not handled carefully (just fine for a drill press, but not an attractive characteristic for your cordless portable...).
Cobalt: The Cadillac of drill bits (always assuming that nothing you get up to at the cottage will require anything diamond tipped), cobalt bits are incredibly hard and extremely efficient at dissipating heat, perfectly suited for metal work. They are considerably more expensive, however, and you're not likely to need a complete set.
My recommendation for the average cottagesmith is a set of titanium coated bits, supplemented by a few individual cobalt bits in the sizes that you find yourself using most often. Of course, you might also consider investing in a set of high speed steel bits, just to have available when your neighbour drops by wanting to borrow your drill...