From Paul Graham’s essay, Writing, Briefly:
I think it’s far more important to write well than most people realize. Writing doesn’t just communicate ideas; it generates them. If you’re bad at writing and don’t like to do it, you’ll miss out on most of the ideas writing would have generated.
Edit, 6-27-07: I often wonder about what traits or habits of mind are connected to being a good writer, and (for example) whether I should try to vote for political candidates who write their own books and speeches. Realistically, though, the benefits Graham identifies of being able to write largely come from the actual act of writing– one can’t benefit from writing if they don’t sit down and do it. So I’d encourage everyone to try to budget time to actually sit down and write, whether they think they’re particularly good at it or not.