Also have a look at the Sigma 30mm f/1.4. 30mm is more versatile than 50mm, though 50mm is awesome as well.
I am not convinced that you need to replace your kit lens. Mid-range zooms are boring, and I don't really see the benefit of a 17-50mm zoom over a 30mm prime. 17mm is not significantly wider than 30mm, and 50mm is not significantly longer than 30mm. (People feel free to correct me on this because I've been looking at the Nikkor 17-55 f/2.8 and Sigma 17-50 f/2.8 for a looooong time and I can't figure out if it's worth dropping money on those lenses if a 30-35mm prime pretty much does the same but better and smaller).
If it were me, I'd get a 30mm-ish prime now, and continue saving towards a wide angle or tele lens for the future.