Yes and no.
In terms of fulfilling requirements, then they definitely have value. As a teacher in NJ, for example, I earn a higher salary for having a higher education. Doesn't matter if I got the degree online at Phoenix or if I went down the road to Rutgers. [Note: I earned my Ed.M. and I'm working on my Ed.D. in person at Rutgers]
In terms of "learning" value for yourself, it depends entirely on what you put into it. If you're not highly motivated and you don't have an intrinsic interest in the topic, then you can skate by in an online class more easily than a small, face-to-face graduate course. That's fine if you just want a line item on your resume, but that's not good if you actually want to learn something. On the other hand, if you're highly committed and involved then you can learn a lot in an online class.
In terms of hiring, I would put preference on a traditional university. If I was looking at resumes and I had to choose between a candidate with a Masters from Rutgers and one from Phoenix, I'd interview the one from Rutgers first. I wouldn't make the hiring decision based solely on that, but in a large pool of applicants it's important to get noticed and get interviewed. That's also not to say that everyone in a hiring position would act the same. The trouble is, you never know who's going to read your resume and everyone has their own biases and opinions.