Why didn't Edward Elric get his leg back? At the end of Brotherhood, Edward sacrifices his gate in order to bring back Al with his body. While doing so, the Truth being associated with Ed's gate tells him:


  You've defeated me. Take everything you want!


So why didn't Ed get his leg back, when he can get everything if he sacrifices his gate?
This is probably difference in translation. In the manga it is made pretty clear. The entire conversation is about Al only. Look at the following transmutations and the sacrifices. Ed sacrificed his leg and Al his body for their Mother. Ed sacrificed his hand for Al's soul. Al gave his soul for Ed's hand. Ed gives up his transmutation gate for Al's body and soul.

I don't remember the entire conversation in the Anime, but in the Manga, Following conversation takes place.
Ref: Chapter 108 of the Manga


  The Truth: Come for your brother, Eh? But how do you plan to extract an enitre human being? How will you pay? Will you offer YOUR entire being?
  Ed: I've got your payment right here. It's really big though. [..]
  The Truth: That's the right answer Alchemist. You've beaten the truth. Claim your prize. All of it.


Thus to me it seemed that the bargain was Al's entire being. All of it. 

Now, you could always argue that the exchange wasn't "equivalent" and Ed should have asked for his leg back as well. We could talk about this all day! But just touching on the very surface, its about the main themes of FMA. Personal Responsibility and Sacrifice. Both Ed and Al are ready to sacrifice everything for each other. But Ed wouldn't use a philospher Stone or even Hohenheim himself to bring Al's body or his limbs back. This has been reiterated several times. In the end Ed is satisfied with what he can get and be normal, because he still has his friends.

Edit: @Maroon also highlights the difference in translation, by mentioning the Cantonese dub. This further supports the differences in translation.


  I'll also note that in the Cantonese dub of the same episode, Truth appears to say something more along the lines of "Take what you came to retrieve, then [now that you've defeated me]!" rather than "Take everything you want!"