I don't look at these forums very often but just had a read. Well, after reading a few posts there is one thing i wanted to say. I think there aren't really high paying niches. Every niche can pay very well. or very bad. There is only one rule: QUALITY CONTENT. Write/publish what you are interested in yourself. If your publications are good, people will link to it and advertisers will target you. Once you get targeted, CPC will go up. If you just list lawyer and cancer keywords, there is a high chance that your CPC will drop to 0.1 -> Besides you will get frustrated and bored. Make advertisers target you and your CPC will NEVER decrease. Your Niche DOESN'T MATTER
Yes, always go to the niche we are familiar or we can never produce quality content. The adsense will be great as long as we are doing it at the right way, niche not the major factor