Definitely be a writer. be in control of where the story goes and can work on a lot more projects. You can plot out very far in advance while you await the completion of the drawings. Plus, writers get most of the credit. It was Brubaker's Captain America. No one mentions Epting even though his art was amazing. Artists switch between books all the time and no one seems to bat an eye lash but if a writer leaves, it is headline news.
Writer. I have managed to write so many fan fictions of X-Men and The Angry Beavers and I would love for some of the stories that I have written in my fan fictions to come in the comics. I can draw a bit, but not as good as some of the best artists.
I think most of us would choose writer since I assume that most of us are pretty bad at drawing muscular humans :P
So are the professionals. Well, maybe just Liefeld.
Good God! How is it possible the editor didn't notice how weird that picture is?!