I laughed the first time I saw that--it fits both Darcy and Mr. Collins so much.

Other little things to watch for:

~In episodes 1 and 2, notice how often Jane and Bingley are together in the background. You can't keep those two apart for anything!
~A bit of a goof: Maria is singing "God Rest Ye Merry Gentlemen" in the Christmas scene, but in one of the wide shots, her lips aren't moving.
~Watch Darcy at Rosings, especially when Lady C is going on about her musical taste. CF plays his reactions to his aunt's foolishness very well.