[cdat]

Oil companies equip them with sensors to do some of their exploration, cheaper then using a manned plane, also allows them to inspect pipelines, etc. Universities and Colleges use them for research purposes, ie, archeological exploration, (along with google earth), terrain mapping, wildlife research, etc. I expect that we will see a huge increase in privately owned drones, large ranches to keep an eye on cattle herds, Power companies to inspect power lines, security companies to protect compounds, etc.
I am not going to get into privacy issues, that to me is a subject that could quickly morph into a very touchy political discussion. Suffice to say, I think drones will become the next major issue for courts to rule on.