One of the burning issues of debate about entities described in UFO encounters is why they look the way they do?
Some people believe that most of the entities look like us, i.e. basic humanoid, because that's the way all extraterrestrial life would look. Other people argue that ETs would be so unlike us that we may not even recognise them as life forms.
A short item in the latest "Discovery Channel Magazine" (February 2010, Vol 3, page 18) notes the formation of a new research group at the University of Vienna in Austria. Astrobiologist Johannes Leitner is quoted as saying "It cannot be ruled out that life forms have evolved somewhere that neither rely on water nor on a carbon-and-oxygen based metabolism." The research group is looking at investigating life based on other elements.