Those last things feel wrong in coffeescript. Honestly, what's more readable:

  x = a ? b : c

or

  x = if a then b else c

And for the last one:

  function() {
    // doing something
    return this;
  }

  ->
    # doing something
    @

Don't get me wrong, I love the fact that I can do nice stuff such as callback?() and some other nifty tricks, but while I'm still having fun using coffeescript, in my experience it's not that great as most people make it up to be.