Personally, I liked Deathly Hallows. Maybe it's not the uber-pwnage or anything, but it was overall, in my honest opinion, a good story. Somethings I saw coming (the Ravenclaw Diadem's location) some things I didn't (Gringotts assault).
! I will agree that the Harry VS Voldemort battle was anticlimactic, but I still liked the dialogue between Harry and Voldemort before the Big Moment, particularly Harry calling him by his real name. The way things had been set-up, the battle couldn't have been drawn out, I think. Not with the whole "Harry is master of the Elder Wand" thing Rowling got going.
! As for Dumbledore foolishly putting on the ring, to be fair the fact it was a dumb thing to do WAS pointed out. Both by Snape and I think Dumbledore himself. It's hard for me to blame him either. The ring was the thing Dumbledore had spent a large portion of his life seeking. He saw it and lost his head for a moment.
I can't help but feel people in general are being a bit too hard on the book. Was it perfect? Hardly. No more than anything else is. For me, though, it was everything I wanted. A good story and a conclusion to all that had happened so far. The epilogue was a bit corny/weak, IMO, but shrug what're'ya gonna do?
But that's just my opinion. I could be wrong.