The Shure SE-215 ear buds I bought are outstanding. They offer a clarity and durability that is seldom matched, and are a bargain ($95.00) in terms of upper tier earbuds.
The technology that makes them sound so good is available in a less pricey package. The feature that makes them sound so good is the fact that they're designed to seal within the ear canal. Effectively blocking interference, and allowing the full frequency capabilities to really shine out. To accomplish, this the Shures came with 3 sets of cushions in different sizes. There are several other manufacturers that offer those accessories, for less money.
*HAVING SAID THAT*
The other reason the Shures are great is that I believe, based on their construction, that they will last a very long time. Probably long enough for me to lose them, but they come with a little carrying case that makes that a little harder to do. The plugs in the earpieces swivel, the cord is reinforced with kevlar, and the device plug is reinforced too. So I expect, barring thieves, that they will be with me for a long time. AND THEY ROCK!