If you are on a budget, and a student learning photography, I would recommend going the prime route.
I very much disagree.
For one, a single zoom is cheaper than a trio of primes covering the same focal length range.
For another, primes are specialized tools. The only time you want a prime instead of a zoom is when the prime does something the zoom doesn't.
It used to be that that meant image quality, but no more. Many of the lenses with the best image quality are zooms, and some of the lenses with the worst image quality are primes in popular focal lengths. For example, the 20mm f/2.8 -- a perfect medium-wide for APS-C, is one of the most "meh" lenses in Canon's lineup. And the worst lens I've ever owned is a Canon 28 f/2.8, which should be the ultimate normal lens for the format.
It also used to be that that meant speed, but not very much any more. While there are times when you want to shoot faster than f/2.8, those situations are rare and marginal. With the high ISO capabilities of modern DSLRs, you don't need the speed for low light shooting. And razor-thin depth of field effects are a specialist "look" of a certain style of portrait photography.
Now, there are a number of specialist lenses that happen to be primes that are well worthy of consideration. True macro lenses are always primes, for example, and lenses with movements (TS-E) are always primes. Until the 200-400 goes on the market, all the Great Whites are primes. The amazingly diminutive Shorty McForty is a prime. And, yes, the super-fast portrait lenses are all primes.
But each of those lenses has something in particular that it does that a zoom doesn't, and it's for that something in particular that you'd want said lens. When you don't need that something particular, though, the zoom is far superior to the prime, as it's literally a bag full of primes in a single lens for less money.
Some will suggest that the big limitation of a prime -- that you can't change focal length -- is somehow a creative advantage. Bullshit -- with a simple piece of gaffer's tape, your zoom suddenly acquires the exact same creative advantage as the prime. And a two-second adjustment gives your zoom the same advantage as with another prime of a different focal length.
So, rattlit, my suggestion still stands: get the 17-55 (and, if you really think you need it, a $2 roll of gaffer's tape).
Trumpet, I respect your opinion and you make some great points.
Still, I disagree that someone learning photography would be better off with a zoom than starting with primes. I think that the biggest parts of learning to shoot are finding/manipulating light (which doesn't necessarily fit in this discussion) and learning to see the world through your camera. To me having a zoom while you are learning acts as a crutch, and though I love the bit about a piece of gaffers tape, I have a feeling that it would be ripped off at the drop of a hat.
That is just my opinion though. Like I said before, I tend to use an old school approach when it comes to learning. I run a small computer animation department but I always look at a candidate's drawing ability even though that has become quite out of fashion in recent times. To me, that knowledge is important. I feel the same way about learning to shoot. I think the basics are very important. In fact, I would consider having a student start with only a "normal" prime until they know what else they really need, or get some recommendations from their school.
I also don't consider a prime a specialized lens. But that's how I shoot and obviously not how everyone else shoots. Perhaps Trumpet's advice would work out for the best.