"30 Rock" season finale: "Kidney Now!"

I know I hardly ever write about NBC's sitcom "30 Rock," but I thought I'd jot down some quick notes about last night's episode as a) this is one of my favorite shows and b)last night's ep was the season finale.
Overall, it was a decent episode. The stuff with Jack arranging the kidney benefit for Milton Green was great, and I didn't even mind all the musician cameos (though can we all agree once and for all that Mary J. Blige is a TERRIBLE actress?). Also, I love Alan Alda as Milton, Jack's new dad. They're a perfect father-son fit, as both are tall, have great comic timing and, weirdly, have only gotten better with age.
However, the rest of the episode was hit or miss. Tracy going back to his old high school was weak, though it is funny that his school is named after Frank Lucas, notorious gangster and subject of the film "American Gangster" (also, this episode featured a little more Grizz than usual. I liked that. I fear the Dot Com overshadows him too often).
And the Liz-Jenna stuff was pretty much a retread of last week's plot.
But that music video at the end was pretty great, and forgave a multitude of sins. So, on balance, a pretty good episode.
Here are a few more thoughts on "Kidney Now!"
* Milton's biography of Jimmy Carter is called "From Peanut to President."
* Seriously, that was the most passive-aggressive game of catch ever. Fantastic.
* Though I didn't like the Liz-Jenna plot, I did like Liz Lemon as a relationship expert. I've never heard of "fruit blindness" before, but it makes total sense.
* The montage of Tracy crying was moderately funny, but suffered from including a clip from this scene, which, let's face it, was funnier than this entire episode. Shut up, Mrs. Rodriguez!
* I see this written in my notes on the episode: "Clay Aiken is Kenneth's cousin. :( Elvia Costello as international art thief. :)" The smiley face is underlined.
* How many musicians did you recognize in the final scene? I, for one, was delighted to see Steve Earle, Waylon on "The Wire." TV rule: including any cast member from "The Wire" on your show immediately ups its watchability factor.
What did you all think?