I didn't even like Amber, AKA Cutthroat Bitch- but Wilson really loved her, and now he's lost her. And House risked his own life to help her, and now has guilt because he's inadvertently responsible for her death. Oh, man. This could be the end of House/Wilson! And poor Thirteen has Huntingdon's. That just sucks. I loved the montage at the end, with Kutner eating in front of the T.V. alone, apparently cool with everything; Thirteen reading her test results with no expression, and Cuddy holding House's hand.
I didn't watch the finale of ER because of Lost, but I heard that had some sad moments, too.