Like many on here, I grew up reading the HP books as they came out- but I also grew up watching the Star Wars movies,and the first book my dad ever read to me (after Hop on Pop of course) was the Hobbit, and when I started reading LOTR and the HP books were some of the first ones I picked up. With that said, Lord of the Rings wins it on both fronts.
As far as the books go, its no contest; LOTR is vastly superior. I loved reading the HP books as they came out, and they certainly qualify as a pop-culture phenomenon- but I can't imagine that they will have the staying power that LOTR has.
As for the movies, the Star Wars franchise is a classic (I agree that the original trilogy is much better, but I tend to enjoy the prequels more than most people- probably because I watched them all in theaters when they came out). I think that the LOTR movies did an incredible job of capturing the "epicness" of the books- even if A LOT of stuff was missing, they did about as good a job as was humanly possible given the time constraints.
Don't really like the HP movies at all, particularly the last 3- not very faithful to the books and certainly none of the movies could stand on their own merits.