My vote will depend on whether you're talking about these "online colleges" (which I personally think are a joke, and most companies won't take a degree from there very seriously. It's definitely better than nothing, and people that go should be applauded for doing something to get a slightly better job, but it's going to take them longer to get far with it. I put them on par with the colleges like Everett or National American University that advertise at 3am and have campuses in strip malls) or just taking online classes when you're in college, as well as regular classes.
As for the latter, I see no problem with them, but I wouldn't ever take a class that I expected to be difficult. I was able to do high school health class as online, and that was awesome. Other gen-ed credits where I more or less had a grasp of the subject and just needed the official credit I wouldn't mind doing online.
But, there's a lot to be said for having a teacher that can more easily explain (and if necessary) visually illustrate, and answer questions.