fishmanlee said:

...or maybe just Anakin

Why? Wouldn't that get confusing? I mean, if his name and his nickname are the same, well...I don't know, but sure seems like it would be confusing.

Ok, for example, let's say Anakin hasn't seen me for 20 years. All his friends call him A-Walk, but acquaintances and introduced strangers call him Anakin. So if someone comes up and calls him Anakin, he doesn't have to worry if it is a friend he's forgotten. Likewise, if someone calls him A-Walk and he doesn't recognize him, it gives him more time to rack his brain trying to remember who this is.

Now then, like I said, let's say Anakin hasn't seen me for 20 years, and I come up and say, "Hey Anakin, you look like hell, did you fall in a lava river or just forget to put makeup on?" Now, if his nickname is A-Walk, he knows he can just cut me down with his lightsaber. But if his nickname is Anakin, he's thinking, "oh shit, do I know this guy?" He can't just strike me down, because I might be Padme's poolboy and she's going to be pissed if she has to find a new one. Meanwhile, as he's debating all this in his head, I take out one of those big oversized boulders you see on The Road Runner and I smash him real good, then steal his car.

I hope this was helpful.