I highly recommend Music and Lyrics.
For some reason I find Hugh Grant funny. I'm not sure why. Even in movies that I didn't love, I respect the fact that he's always funny. Notting Hill, American Dreamz, and the very good About a Boy are some examples. This movie is genuinely funny.
What makes this movie work is the fact that the music is original and well done. The 80's tunes are deliciously 80's. The modern Brit-tina Spear-ulara tunes are actually clever ("Buddha's Delight" is unmatched; I can actually listen to this song for enjoyment purposes). The big thing about the music is that they don't dumb it down or say "look at me, look how clever and obvious I'm being." The music works because they sell it, unashamedly and without blinking.