I'm in the undecided camp - but I'm certain of one thing the crop circles that have appeared overnight in areas of England certainly aren't manmade.
The famous Doug and Dave crop circle hoaxers of the early 90's (I think) could never have produced the intricate patterns which have us in awe.
I remember one serious study done by a German guy around the same time - he looked at histology of the corn, electromagnetic studies in the circles etc - very detailed real science. It concluded that the only explanation for the observed data was some sort of gravity wave!
I remember there was one story in the book about a night when the crop circle researchers repeatedly stumbled over British army patrols in the same area one night, and still with all this activity there was a magnificent crop circle in the field below them the next morning.
Maybe it's the British army!
Look, I don't know what the hell causes them or what they're about - I just like to look at 'em. Kind of like women!!!!!
Cheers all
Doug