How will you be using them -- for example, will you need isolation, as for bus, train or plane travel? Or do you want just an everyday kind of earphone that provides pretty good sound and that can stand up to getting thrown into a backpack or briefcase on a regular basis?
Isolaters would generally cost more, and might sound underwhelming (or "un-fun") at first, but something like the Etymotics ER-6i's would really add to your commute or travel experience. The Ety's look insubstantial and don't pack as much boomy bass as many consumers have come to expect lately, but they reveal things in your favorite music you'll be noticing for the first time while blocking out much of the outside noise. These come in white or black, and can be found on the Web at a variety of prices, some of them excellent.
I'm sad to no longer recommend the Shure E3/E3C's (I don't believe there's any sonic difference -- perhaps just a color or model designation). The Etymotics ER-6i's sound better, isolate better and cost less (to my ears -- of course, your mileage may vary).
At a lower price point, you can choose The Sennheiser earbuds [edit: canal phones, actually], and I recommend the cheaper Creative EP 630's, which are virtually the same thing (check threads for that endless debate). The Creatives are an excellent buy, and while they do have some cord microphonics (I don't know whether the Sennheiser version does), they would be nice to have -- either as a main pair or a backup pair.