I LOVE the Harry Potter movies! I had a hard time getting into the books though.
But I read all the Twilight Series. I liked Twilight movie too and the soundtrack. And I haven't seen New Moon yet but I'm sure I'll like it because I thought that book was the better of them all. But the soundtrack sucked.
So....IF I HAD to make a definitive answer.......I would say Harry Potter was better.
I love the "hotty" charactors in the Twilight series. Gorgous! Both Edward and Jacob. But Robert Pattenson as a person, is ssssoooooo completely different from his charactor, I don't like him. And Kristen Stewart too. The other actors seem pretty cool. Like you might actually want to be friends with them. Maybe get to know them. Same in Harry Potter. Those actors seem like real, down to earth, not shallow and self absorbed.
The 2 series shouldn't be compared though. They are so different in comparasin. Twilight Series is about LOVE between a girl and a boy. And Harry Potter is more about mystery and magical and survival of the fittest. If that makes sence??