He's the guy who gives R-rated comedies an emotional center. All of that is true, but it overlooks the element of sound and his ear for music. Right now, he's the best at accenting, augmenting, and, indeed, improving his films through the music selections he makes. In my opinion, no movie in 2007 benefited as much as Knocked Up did from its soundtrack. (This would be a good time to note that I didn't forget about Todd Haynes' I'm Not There, it's just that that movie is about Bob Dylan, for crying out loud. Hardly fair.)

The use of "Shimmy Shimmy Ya" right off the top is absolutely perfect. Guys being guys, doing stupid stuff to the sounds of Ol' Dirty Bastard. Awesome. I can't help but wonder why they changed from the song used in the previews, where Ben Stone (Seth Rogen) raps along to a song that I can't even refer to by name (without the use of asterisks and other symbols) from the first Wu-Tang album, but either track works in this spot.

The shift from Ben and his gang of merry mad men over to Alison Scott (Katherine Heigl) and her world, where she lives with her sister, Debbie (Leslie Mann), and brother-in-law, Pete (Paul Rudd), is punctuated musically. The dichotomy between the two lead characters is obvious, but in case there was any doubt, Apatow made sure we got the point by swapping out the pulsating piano strings of the RZA-produced "Shimmy Shimmy Ya" in favor of a very delicate instrumental from Loudon Wainwright. The song is recognizable as "Grey in L.A.," which can later be heard in full form playing over the back end of the closing credits.

Staying within the first six minutes of the movie, the scene shifts back to Ben, Martin (Martin Starr), Jonah (Jonah Hill), Jason (Jason Segal), and Jay (Baruchel), where they launch the "dirty man competition" involving Martin's beard (initiating the best running joke in the movie) and engage in discussions regarding their "business" (finding nude scenes from movies and putting them online). The song used in the background? "Santeria" by Sublime. You could not possibly come up with a more appropriate song for a bunch of slackers who likely were freshmen in high school in 1998.

The songs selected for the club scene where Allison and Seth first meet aren't quite as pitch perfect, but I like the eclectic mix of Damien Marley ("All Night") and the hip British song de jour (Lily Allen's "Smile") for background noise layered under key conversations (the best line came courtesy of Segal: "It's not herpes if it's everywhere"), and the switch to "Swing," by Savage for the dance floor action, where Ben hopelessly uses his one move (the "dice thing") time and time again. I'd never heard this song and it isn't one that I would ever play in my car or on my iPod, but it was ideal for the scene.