Cyclops probably gets the rawest deal out of anyone in X2, since he's out of commision for a large chunk of the film, but his moments come at the end, after Jean dies--especially that final exchange between him and Logan. It was the first time I actually believed the film embodied the standard decripton of Cyclops "carrying the weight of the world on his shoulders."
Xavier gets his fair share of screentime, though. His interactions with Magneto, Stryker, the hallucenation where he's able to walk and he starts crying...to that last look he gives at the end of the film (which promised so much, and we're going to get so little of that).
As for the Lady Deathstryke fight, well, I like it a lot. I think Singer got a little too zoom happy for parts of it, but it was pretty brutal, and actually showed why Wolvie stabbing her multiple times didn't kill her, which they bungled in the first one with the Sabertooth fight.