Not to disagree with you, the nifty fifty is a cheap and fast lens, but what made the nifty fifty so popular is that on a 35mm body, it was a no-zoom lens- that is, what you saw with your eye is what you saw through your camera (roughly).I recommend a fast lens, like the Canon 50mm prime.
Natural light images tend to look better, and to require lower ISO settings, creating much less "noise".
For that reason, it is my personal opinion (and it is just an opinion) that a 28mm prime is better for APS-C cameras (30D, 40D, 50D, XT, XTi, XSi, T1i, T2i), and that a 35mm prime is better for APS-H cameras (1D, 5D). The reason I say this is because they emulate what I consider one of the most important parts about a 50mm lens on a 35mm body. Nearly any prime can be made to be relatively fast, but there is a reason you don't see people running around with a 200mm f/1.8 lens for general purpose photography, the focal length doesn't make sense in nearly every situation.