The HP laptop will be super convenient to use and great for watching films and listening to music on the go. On the other hand, when the laptop dies, there goes her nice speakers. I've always thought that separate speakers produce better sound because they aren't trying to fit a certain mold the way that built-in speakers do. They aren't as convenient to cart around though, and I'm assuming she has a laptop instead of a desktop for its portability. So I'm voting for the HP laptop that has Bang and Olufsen speakers.
I bet she'll appreciate whatever you get her though.