YA Fiction Recommendations

As the title says really.  I'm not too up to date with YA fiction but would like to get a friend's daughter some books for her upcoming 14th birthday.  She is a big reader and demolished the Twilight saga over Christmas, read Harry Potter years ago and I think she has read the Phillip Pullman stuff (if that's the golden compass series).

So if anyone could be kind enough to recommend what is good/popular at the moment please.

Thank you.