i will disagree a little bit and say the 24-70 while not 100% usable is passable indoors, and under the right circumstances is fine, even without flash. is it as good as a prime, of course not, but it's a matter of compromise. my 24-70 is on my camera 90% of the time. if i need to go out of town and only want to bring one lens, i feel comfortable that the 24-70 will do the job, whereas with the 30F1.4 i'm always a little hesitant.
if cost is an issue look at the options from sigma or tamron, the results look comparable if the build quality is a step down.