[ChrisRabior]

Something to keep in mind..
When you speak about shooting concerts, there are two entirely different scenarios. The first is if you have access to very well lit venues. This is basically when you get a photo pass to a major event. These are very well lit, because people need to be able to see from way in back. I've shot a few like this with a 75-300mm f/4-5.6 (the non-IS version).
The second is the typical concert. Local venue, bar, anywhere with less than optimal lighting. For these, you HAVE to have a fast lens. I've shot a few shows with my 50mm f/1.8 at 1600 ISO where the only way to get a decent shutter speed was to underexpose by 2 full stops and try to bring out the shots in Photoshop.

My guess is you'll be shooting with the less than perfect lighting conditions. If you're happy with primes, that's probably your best option. 85mm f/1.8 is in your price range, and that's a pretty nice lens for concerts. If you're looking for a zoom lens, then the lowest you'll find is a constant f/2.8. That being the case, my earlier post covers the entry level lenses for that. Once you start making the big bucks, you could upgrade to Canon's L glass.