It's true that I don't readily notice music alot of the time, especially if it's there just to provide a background rhythm. It seems to me that alot of the music used in exercise videos is quite similar and very repetitive (you'll hear the same Dynamix track in several different vids in a CIA series, for example)--that gets pretty old pretty quickly.
I do like recognizable songs in cardio videos (a la BodyPump and Christi Taylor...she evens sings some of her cues!) although if I really like and know a song, I'll sometimes concentrate on that more than on the task at hand! Cathe usually makes pretty good choices, but they fall more into the background rhythm category for me ("Uh, uh, uh, Everybody..." from Rhythmic Step comes to mind--perfect BPM, but that phrase just goes on and on...). Using more unsynthesized vocal material and generally less homogenized mixes in the new tapes might be a nice change. Just my 2 cents!