it depends mainly on how big the venue is, and what kind of pictures you prefer.
If you really want to cover a whole concert in pictures, you will need both portraits of all the members and whole-band-pictures. I often have a 35 1,4 in my bag if the venue or show is really dark and I really love this lens. But I could not imagine to shoot a whole concert with this lens, because I would miss too many scenes.
There are many situations where you will wish for a zoom lens. Jumping guitarist, a singer climbing on the drum raiser,...
So actually, I would recommend you the 17-55. Look for a used one, it will hardly stay new and shiny if used on concerts. With the 17-55 you can shoot overwiews (do you say that in english? sorry if not) and have the whole stage when the lighting looks good or the band is dancing around, and you can shoot portraits without cropping too much (but without cutting body or guitar parts off).
On my 7D, I am using the 24-70L, but only because I also have the 10-22 with me. I often use the UWA in smaller clubs or for the audience. If I had to choose only one lens - I would go for the 17-55 and if I need a close-up - just crop afterwards if there was no 70-200 in my bag.
The can be canon or 3rd party (although I'd like to stick to canon just for the peace of mind that there's zero chance it will stuff up my camera). I want a light, fast (max of 2. lens to shoot live concerts with (right up at the stage where security are). My really stretched budget is $1500, give or take a bit ($100).
Considering these lens;
* 50mm (canon 1.4 or sigma 1.4, although I've heard good/bad with both but heard sigma is worse..?)
* 24mm (either L or non-L)
* 35mm (either L or non-L, considering this as its like 56mm on a crop which is what i have)
* 17-55 2.8 IS (trying to stay away from this since its EF-S and will be moving to FF in <5yrs)
* sigma 17-50mm 2.8 (I think it has IS, i like the focal length. but it's 3rd party and i heard 3rd party have a decent chance of screwing up electronics in your camera)