Agreed! I only think of algae as a nuisance when it gets out of control. We have a problem with calurpa (don't think thta's spelled right) in the one reef tank, it's overgrowing a lot of the zooanthid rocks, so I take one out and put it in the reef with the sailfin tang, and after he cleans it off, I switch it out with another.
I really don't mind some green algae, though, not only is it food, but it makes thing look a little more natural. I'm sure that most rivers, streams, and ponds are not algae free.