The heck with H/G or H/P or even H/G/P. The new improved Harry needs a Slytherin woman -- I vote for female!Blaise, Daphne Greengrass, or someone similar.
Remember, he's not the person he was the day before this story started, and he won't be the same Harry that hooked up with Ginny. He's more mature, more experienced, and has learned the values of tact, intelligence, and cunning. Where's he most likely to find this? In Slytherin!