I've been wondering about that myself. College education is fairly cheap in my country (around 400-600 euro per semester) and other costs are not too high (most literature is available in libraries, student housing for out-of-town students is government subsidised for the most part, as is food and transportation, etc.), but I'm still not sure about it being economically viable, if for no other reason then because of the money that I could have earned if I got a full time job straight out of high school.
Now, some high paying fields do require specific higher education (private medical practice, law, etc.), but those schools are hard to get into and even then it's not a guarantee (most doctors don't really make all that much and neither do most lawyers).
All in all, I'd say it's worth it if you have something very specific in mind. However, going to college just for the sake of going to college is a waste of time.
Personally, I got screwed, since I wasn't sure what I wanted and wound up spending over 5 years to end up with degrees in linguistics and anthropology. Since due to the ongoing financial crisis the various scientific institutions where I'd normally look for employment are not hiring at all, I can't get a job in my field and I lack the inspiration to make something happen myself (again, I only took those majors because it sounded interesting and I had no better ideas).
Now I'm regretting it.
Sure, a college degree looks nice, but I'm likely to end up with a job I could do with only a high school education. I would have been better off taking a year or two or three and just working a job while I figure out what I want to do. Also, now that I DO have an idea what I would be interested in, it's too late and I can't afford to go for another 3+ years.
I'm guessing it's even worse in countries where it's pretty much cheaper to buy a house than go to college. I'd say only go for it if you really belive in what you are signing up for. Otherwise, get a job or just go traveling. You'll end up with waaaay more money in the long run...