Accepting what is possibly a life-long employment requires great amount of introspecting, so making the decision wasn't easy. In my professional life I value, above all, doing cutting edge research. However, I can do so both as an industrial researcher and as a professor, so this did not help me to make a decision. I also did not have particular constraints (e.g. a family) that could steer me in either direction. This freedom made the decision process truly grueling and exciting at the same time! :) To my surprise, I found myself alone in actually deciding. Every single person I approached with my problem was either passionate about academic or industrial research, but never both. Except for cheering along the lines of "how wonderful it is to have such a choice", no help was offered :(
A great advise came one day from my great advisor, Sasha: "Don't make the decision until you are very comfortable with it. Until you know you won't regret. I find that it's always helpful to take a few days. In my anecdotal experience, something usually happens that will help you decide: a thought comes to your mind, you talk to someone. So take your time and decide when your heart tells you that you are ready to make the choice and you will be happy with it."
Although some people would disagree, I suppose the question here is whether I see myself as a professor for the rest of my life. If I don't, no point in returning to industry a few years later, might as well not leave the industry altogether. I could see myself teaching in academia, as I enjoy teaching quite a bit. Also, the title "Prof" would have given quite a bit of a kick to me just by itself. I have read and re-read all three pieces on the academic interview process by Matt Welsh. It helped me a lot through the interview process. But I have also read his post on the other side of academic freedom, and I recommend it to those folks who are deciding. While it is true that the academic jobs are extremely hard to get, I disagree with the notion that you could always go back to industry, if you decided academia is not for you. Such decision would be even harder to make. Plus, I would not respect myself if I left university in the middle of my tenure track process, which would mean staying in the school for at least 6 years.
One thing I realized about myself is that I absolutely cannot live without access to the cutting-edge technology available in industry. Hacking prototypes of systems that are due in 2,3,5 years that you know will impact the life of many millions of people is absolutely thrilling, and almost impossible to do in academia, because the early technology is usually a company secret. Thus, I have decided to stay in industry. I feel I made the right decision, though, admittedly, a very difficult one. My hope is that others would find this rant useful if faced with similar choice.