+1 to what clayne said.
You have to know, where you are going to know which lenses are right for you. What good is it, if we all recommend some super-wideangle while you prefer animal photography or a monster-zoom if you only like landscape and street?

The 50mm is a good start and you can use it for almost everything - do so and you'll become a better photographer in a few more months or a year. I started out with an old 50/2,8 and used it exclusively for almost a year and it helped me greatly by concentrating on what's necessary and being pretty close to what I saw with my own eyes. Also zooming by walking keeps you fit

Or if you already know exactly, what you like, tell us