#6 I ranked this one without seeing the close up - I felt it conveyed the message well from a distance. I'd worry about it's use in black and white and on some backgrounds as to whether it is too messy. I like the old "wanted" poster type of writing for the words. I think the environmental message probably needs to be included.
#5 This is a great design and probably one of the most artistic, but it doesn't have quite the "feel" I was looking for - great feedback I know! I'm not sure how to describe the "feel" issue - but that's why I'm a scientist and you guys are the creative ones I guess.
#16 it does get a bit messy in black and white I'm a bit worried about how it would play on letterhead or business cards. Still really like the overall look.