[lobster_johnson]

Sure. IO plays a part of a larger system of monads and functional programming, but it's not a prerequisite for impurity to exist -- it is more like a happy confluence of various strands of functional theory. After all, Haskell had I/O before the IO monad existed (although it was apparently not a happy solution).

Personally, I find monadic I/O theoretically elegant, but it comes at the cost of clumsiness when applied to real-world programs. To me, Haskell's "do" blocks feel like an implicit admission of this clumsiness; they are a crutch to work around the fact that having to constantly wrap and unwrap data is something of a chore.

[fusiongyro]

I guess I just don't see them that way. Most of the time my code is in pure land, and I don't avoid "do" when the result is more readable. I think the ugliest thing in Haskell is probably monad transformer stacks, but that's mainly because I think they're overused by folks who create more abstraction than they need as a matter of habit.

That said, the kinds of things I do on the side with Haskell tend to have a small, well-defined I/O surface, so it could be that I'm spared the worst of it by my interests. I suppose if that weren't the case I'd probably favor OCaml more than I do.