[steven]

It is more of a regional thing, I'd think. There is definately more what they call "feminine" language used by men in the Kansai region, as MMM said. I don't live in Kansai, but linguistically speaking, it's closer to Kansai than it is Edo-ben. Because of that, men here are more prone to use more feminine language, which is something I think I like more about Kansai-- there's a bit more flavor in the language. As far as my experience goes, I've never heard a man referring to himself by his own name without having it be used in a joking manner. People do it, but it's usually for comedic purposes. It's not something I'd ever do in the workplace.

As Sashimister pointed out, you can use just about any words you want. I've head a guy say "Atashi" before, too. He was clearly そっち、though. The language that you use, especially how you refer to yourself and who you're talking to totally changes depending on the situation. I probably use おれ、わたし、and　ぼく all in the same day on a regular basis. I'm not gonna look my boss in the eye and say おれ, because it just feels weird and out of place.

Another thing that I've noticed is that you can even call other people ぼく or おれ if you want to. I think it's usually looking a little bit down on them though. It's funny because I've even called some of my students (the girls of course) あたし, which usually gets a laugh. That could be a regional thing, but I've head it used enough times to confirm that it's not just something that a small group of people I know use.

Nyororin, I have to admit that at one point I was under the impression that ぼく was childish, too. It was right before and right after I got to Japan (to live here). I don't have that perception anymore, but I do know that most of my elementary school students would write "ぼく" whenever they wrote something-- and they would say "ぼく" during speeches. During most conversations though, I heard a lot more of おれ. In a sense, I'd see おれ as being more little-boyish because little kids (and even young adults) seem to use it to their teachers/elders etc. That might be a misconception on my part though... I've heard/seen that happen so much that I guess it's just how students talk to their teachers. There's also the inaka factor, which I guess implies that the language here isn't as "sophisticated" as big cities (which is how I think a lot of people look at it).