2d or 3d Art? Which do I prefer?
I don't necessarily want to take the easy way out and say "they each have their own uses", but I'm probably going to say something like that anyways..
The thing about 2d art, or "surface" art, is that nearly every art piece uses it. If I were to make, say, a cardboard dragon, even though it is clearly a 3d piece of art, painting each of those surfaces with a nice pattern is a "surface" art. (I'm sure there are better exaples)
Answering the question though, I prefer 3d art. There is just something about it being so there in the present, taking up space, that makes it more appealing to me. Yes, that means giant murals have that effect on me too. But sketchbooks (though I love them), as well as canvas paintings, just don't get that "Wow" factor that a 3d piece does.
I like it when the concept drawing has to be drawn from more than two angles because there is so much more offered in the third dimension than available on a piece of paper.
Short answer: 3d, long answer: both.