Which part of those songs do you hate? The songs themselves or the singers? There isn't a single song in the game that is actually performed by the original artist. And the Cher song is a bonus stage, but that only means that you likely won't have to play it on easiest difficulty and depending on how good you are, possibly the second easiest difficulty.
If it's any consolation, the Ashlee Simpson, Cher and Avril Lavigne songs are all rather easy to the point that you'll very likely be able to beat them on your first time through. "
The only songs that I didn't like were Jamiroquai - "Canned Heat" and David Bowie - "Let's Dance", mainly because they pissed me off so much while playing them. The beat markers didn't match up with the song. :angry: