This was one of the most touching a beautiful episodes of House ever written. The entire cast played their parts perfectly.
I thought the relationship with House and Wilson got a lot of insight in this episode. Wilson's caring attidude seemed to clash with House's "jerkishness". Nevertheless, I think House was a lot softer on the inside in this episode. He wanted to help end the childs suffering- his critism was of her mother (unfair critism, it is devastating to lose a child), and it was clear he was more concerned for her prolonging her suffering for an extra year.
I thought the whole Chase kissing the girl thing was excellenty portrayed, and also very amusing when House deduced it. I also loved Andie giving House a hug at the end, and promptly inspiring him to live life more, seen at the end when he rides the motorcycle- another insight into House's passions before he injured his leg.
Overall, this episode was exactly why I watch the series- it was funny, dramatic, moving, brilliantly acted and wonderfully written.