Originally posted by sterretje First determine the focal length that will work for you in the intended environment. You can do this by putting your zoom lenses on a fixed focal length and check if you can get the composition that you want.
+1 on this idea, you can set the 16-45 to both 45 (close enough to 50) and take a few shots, then move the zoom to 35mm and take a few shots. Which one is best for you? That will give you an idea of which way you want to go. I'd recommend the 35mm f/2.4 but I like wide so I'm predjudiced. :P
NaCl(if you really want to be precise use the 50-135 for the 50mm shots)H2O