Favorite: Tempus Anyone?
I'm a huge Tempus lover. So any episode with him in it is a good one for me. Thats why I love Season 4 so much, because he's in there more.
Least Favorite: Big Girls Don't Fly/Clone Arc (tied).
Hated those episodes. BGDF depresses me, even though I know it gets better again in only 2 episodes.