Well. If you're talking about listening to music or some kind of crap like that. Then sure. Speakers indeed. Here I was under the impression that you were talking about gaming. But sure.
Now I'll say why I prefer listening to something with speakers. Because I love by myself, and have no need to be quiet. I can still wear my hat when listening to something via speakers.
But. I think I'll elaborate on why I would vote "it differs" when I still thought this was about gaming.
I usually enjoy headphones most. Firstly because then I get the sound imediately. You know. Close to my ears and all. So I'm a lot better at defining where the sound came from. And since I don't have a surround either, it's hard to determine where the sound comes from when using speakers.
Why this is important you ask? Well. I'm playing a lot of FPS games, and games where you have to be on your toes. Especially the online ones.
But there is also another reason as to why I like headphones a lot more than speakers when playing. Because I tend to hang around on skype with friends when playing. ALso teamspeaking alot too. So I have a need for the mic that's on the headphones. Now I do have the seperate mic too, but I like the headphone one (Probaly like everyone else) a lot more. Because then I can have my head wherever I want, and still be able to talk ...
As to speakers, though. When I'm not playing those kind of FPS, or not hanging on SKype, I enjoy playing music. And I really prefer having my music on speakerl, since it gives me a massively better experience than headphones. Oh and I don't have to be quiet =D