Actually, I belive the second line is:
Originally Posted by mugglegurl
"Poor people have it, rick people want it." Because rich people supposedly have whatever they want, so they would want nothing.
At least, I think that's how it goes.
Warning! Some unimportant DH spoilers below!
Also, yes, the riddles are the same for all people (McGonagall is given the same one as Carrow) but would the door accept different answers?
Like Luna's answer. Obviously somebody like Hermione woudn't have given that particular answer. Would they be left out of the common room, or would the door accept multiple answers for the same question. Remember, the door doesn't say "correct", it says things like "nicely phrased". So it seems like it would accept different answers.
End DH spoilers!
But here's a differnent type of riddle.
Where do chickens come from?
You could say "the egg because their life begins once they emerge from it" or you could also say "the chicken who lays the egg because that's where the egg comes from".
It's kind of a twist on the chicken or the egg question.
I hope I helped some!