What's Cool?

This is usually thought to be cool:

And this is usually thought to be not cool:

Right? Or not? Is one cooler than the other? By cooler I just mean more acceptable to people who care about these things. I'm sure most people couldn't care less! But say you are something of a music buff, which one would you think ok or even interesting and which not? Or what about this one:

 
I'm still thinking about this, so why not leave a comment?