I wouldn't get a zoom unless you just want one lens to do "wide angle" and normal view. On a crop, really wide angle doesn't even begin until you drop to around 14mm and less. 10mm, 11mm, 14mm and 16mm are your break points really, in wide angle. There's a few 8mm out there, but they're fairly extreme. Don't know how extreme you want to get. Combine that with the need for low light performance, and you're going to meet a bust. Wide angle and zooms for wide angle just don't have great low light performance in the form of really wide aperture and things like IS, etc. The reason being, wider aperture means bigger physical parts in the camera, and wide angle being such a short focal length, it's hard to physically make that work. Most super wide angles just won't top out apertures beyond F2.8. So that said, I would get two lenses. One for wide angel. One for low light performance.
On a crop, look at the Tokina 11-16mm F2.8 DX II or the Rokinon 14mm F2.8. That's wide angle with a splash of low light. Or get the 10-22mm if low light isn't a priority on the wide angle.
For the low light lens, the EF 24mm F1.4L woud be my top choice, unless you need wider even still.