I am working on an online Master's degree now. I will likely finish in the spring of this school year.
I couldn't actually attend my university if it weren't online. I also work full-time, so the online format is more convenient.
Even the top-notch schools have online classes. The HW, projects, and grading for the one I'm in are exactly the same as for on-campus students (except for one class w/ an in-class participation component). So I don't think there is a drop in quality of material covered.
Some other programs:
Free Online Course Materials
Autumn 2007-2008
We do miss the face-to-face interaction with professors, and peers.