I like both HP and Twilight, but Harry Potter is definately the better series. In my opinion.
I like Twilight because for some reason I get captivated when I read those books. Edwards annoying, Bella's annoying, SM's word usage is annoying, and the whole 4th book is so bad it should be illegal, but I still like reading them. It's just one of those books you slip into lol. Oh, not to mention there's no plot and/or character development. Yeah.
The movie's.... Eh. The only problem I have with it is the overall dead feel it has. The whole time it's just like.... Blah. I didn't see New Moon yet.
Harry Potter is a very well written series. And I was very pleased with the last book. I know some weren't, but I liked it lol. The books have good plot and character development and they're just exciting to read overall.
I like the movies; I think their doing a fantastic job with them. Except for OotP, but that's just because it's waayyyyy too fast paced and condensed. They left out so many details it's amazing. Plus OotP is my favorite book of the series, so that made it all the worse for me lol.
But anyway, I vote Harry Potter XD