"Oh, Harry!" alright. Haha. I found a list somewhere (I forgot the site, I think it's HarryandHermione.org sorry). It's about why H/Hr is better than R/Hr. It said there that "Oh, Harry!" is better in bed than "Honestly, Ron!"
Too bad DH didn't end up H/Hr. That could have justified the "Oh, Harry!" catchphrase. But nevertheless, the H/Hr moments in DH gave us some things to squeal about.