Without doubt, Marshall against Man utd in the 2-0 FA Cup win at Old Trafford. The ball heading for his top left hand corner, but somehow tipped it round the post. Phenomenal save.
http://www.youtube.com/watch?v=O83e-_rHiA8
I agree with the the Westwood V Birmingham one! One was Banks-esque if I remember right. Not sure how he kept it out.
And the Marshall one at Old Trafford was good too.
From an opposition perspective, I recall Crewes keeper keeping out everything last season and some of the chances we created he done well to keep them out