I embraced the spoilers for this movie, but I exercised enough restraint to leave the shrinkwrap on the soundtrack until I saw the movie.
My favorite song is, far and away, Interrogation Song. I love fast & furious patter songs. Ask me about my Gilbert & Sullivan collection someday. After that, We're Doing a Sequel, Scooter's adorkable cover of Moves Like Jagger, and The Big House. The only one I didn't enjoy was the Oscar-bait Something So Right, because Celine Dion ruined it for me. I kept wondering why she was horning in on Miss Piggy's emotional scene, and when she faded in and covered a third of the screen at the end of the song I fully expected Piggy to swat her away, snapping that she was having a moment here.
I got a kick out of the demo songs. Some people said that McKenzie's Muppet impressions made them cringe, but I thought they were cute. He really got into it, working on the characters' delivery like that. Bravo.
Oddly enough, I received my copy just hours after returning from my first viewing of the movie. All of these songs were great, catchy tunes, and I can't choose any favorites. Many of the songs are incredibly humorous (and "Something So Right" is incredibly heartfelt), and being able to hear them in full is definitely a treat. And I'm also glad to hear the lyrics clearly. I believe I mentioned this in the "Your Thoughts on Muppets Most Wanted" thread, but when I went to see the movie, the music was so loud that I strained to hear the lyrics. And then I wondered if my eardrums were going to explode.