Whatever someone wants to show is up to them in my opinion, I wouldn't make any real assumptions with regards to morals, intelligence, personality, etc.
I'm a fan though.
About cleavage at work though, reminds me of a situation I ran into a couple months ago when I walked into the office of my team's HR rep. She had big time cleavage going (i.e. feelgood's second picture) and here I am doing my darndest not to look, for fear this was some kinda sick trap they try to get managers to walk into... hahah