Lillix
"I hate you, I love you
I just can't remember to forget you" from It's About Time
Read all the lyrics to Falling Uphill

My Opinions and Recommendations
Lillix is a girl group that combines a great mix of punk and pop. There album, Falling Up, has a lot of great songs, but unfortunately, a lot of the songs sound alike. My favorite songs on the album are Dirty Sunshine and 24/7. They also do a good cover of What I Like About You, that I think is better than the original.
If you already like Lillix and want to hear more like them, I would initially suggest Pink. Pink is also a mix of punk and pop that leans more toward the pop side. If you want a little more pop, try Ashlee Simpson. She has some edge, although not as much as Lillix. Finally, try a ska type band like Save Ferris.
Buy Lillix's Music