I ended up getting both, right now in my bag I have
18-55mm kit lens ( though I'm repalcing that next )
50mm 1.8 ( i got it for free because it was broken, took it apart and fixed it )
I prefer the slightly wider angle of the 40, but the 50 is amazing in low light situations. I really wish they had an affordable 20-25mm fast prime.
Edited by Jixr - 6/29/13 at 9:10pm