Aw gosh...This is like asking someone to pick their favorite child. sweatdrop
I'd have to choose LOTR, but Harry Potter is really, really close in ranking! I just think LOTR is a little bit better because it's a whole new world full of rich detail and unique characters. Not to mention Tolkien has written other books linked to LOTR and The Hobbit that explain the different races, histories, etc.
Harry Potter is just as well, but I've given it a few less brownie points than LOTR because it happens in our world, rather than a whole other...
As for Star Wars...Well, I love the movies, but I really haven't had a chance to immerse myself in that universe very much yet.
So there's my useless rant for you...Enjoy wink