For real low light pics with a film camera, get yourself an f1.2 or f1.4 50mm lens.. I don't think those will fit your rebel.
they will fit the rebel, but a 50/1.4 is going to set you back a lot of pennies.
A rebel can take both full frame lenses and AF-S (1.6x crop) lenses. The 10D was the only canon that had problems with full frame lenses. Just remember, with the crop, a 50mm will already get you 80mm. Almost all my lenses are full frame lenses and they work just fine on my 20D - you just get a longer zoom range.
From what I've noticed, you can do pretty good in most lowlight situations up to f/4, sometimes more. I've used my 70-200/2.8 from the back of the room and have gotten decent shots. Just set your camera to burst mode, where it takes a bunch of pictures from just one shutter push. One shot might be 5 pictures, 4 of which might be blurry crap, but theres a good chance at least one will be decent.
And as far as I'm concerned, a little noise from high ISO's in concert photography doesn't really distract from the image at all. It goes with the territory.
Good info man. i'm gonna give it a try and pull the filters off my shit for the next show.
Yeah, I asked a bunch of people about filters when I got my 70-200mm, I wanted to protect it since it was so expensive, but the response I got was pretty much not to use it unless I needed it. I still use the filter on it in most concert shooting, but if I use it for anything else, I take the filter off. I never got filters for any of my other lenses, I'm just extra cautious when I have the lens cap off. And the second I'm done shooting, the cap goes back on. I always use a lens hood as well for extra protection.