Excellent post Gak. After posting today reguarding James Randi's million dollar proposal, I was thinking about this very thing on the way to the hairdresser (isn't walking great thinking time?). I considered that testing these things is very difficult indeed, especially if one doesnt fully understand them. Hell, I don't claim to understand this myself. The very nature of it is extremely hard to explain - there are no adjectives to describe this energy stuff and I always end up with elaborate metaphors.
I continued this discussion with my hairdresser - she wasn't quite prepared for this - hairdressers are brilliant at small talk but an actual discussion was quite welcome, if not somewhat unexpected, she explained. She thought that this energy sensing ability may just be an enhanced form of the common ability to 'read' people, ie: to tell when something is wrong with your friend, to pick up on suggestive signals from the opposite sex etc, you know the stuff. It's quite intuitive at times, and some people do it better than others. She suggested that this "people sensing" ability might be related to this "energy sensing" ability. I don't happen to agree, but I think its a good point and I'll look into it, Gak might want to also.
Me and my hairdresser's two cents
Reguarding auras: I think that auras are quite different entirely. One actually visually witnesses auras, as opposed to using some extra sense.