I loved Draco breaking Harry's nose so much more than I loved Draco crying in the bathroom. It is the result of having read too much bad fanfic, which is hardly JKR's fault, but still.

So, yes! Nose-breaking!Draco!

I thought chapter 24 was important too--more in terms of the HBP than in terms of the bathroom scene, to tell you the truth--but chapter 23 tied together so many plot-points and introduced so many more!