1. Ginny admires and adores him. She seems more devoted to him than to any of her brothers. Perhaps it is an oldest/youngest dynamic. He has a sort of "hero" status for her. She is protective of him and whatever he says seems good enough for Ginny. Since Ginny has become so important to Harry, I think this will factor in to the story.

2. Bill is a Curse Breaker. Harry is dealing with Horcruxes, which are protected by complex, Dark Magic that barbequed Albus Dumbledore's arm (we don't know exactly how the Headmaster's arm was charred, but it had something to do with that Ring Horcrux and/or its protections). We have heard enough reports about the Curses on the Egyptian tombs that have been Bill's specialty to know that he is adept at finding his way through such complex and dangerous magic. I believe that Harry will accept Bill's help, eventually, and it will prove key to at least one Horcrux adventure.

3. The meanings I have found for the "hor" in Horcrux are mostly Egyptian. There was an Egyptian King named Hor, who was found in just the sort of tomb that Bill would have been unearthing. The God Horus is a very important symbol to the Egyptians as well. There is also the Biblical reference of Mt. Hor, where Aaron died. More on this in another article, but suffice it to say that there is a good chance that the very idea of the Horcrux has something to do with ancient Egypt, which is Bill's specialty.

4. Bill and Fleur are getting married. I kept wondering about this one. Bill is smart and handsome and successful. But aside from this, he has always seemed very level-headed and down to earth. He seems to honor things of depth and quality, and to keep the values that Arthur and Molly taught their children. While Fleur's charms are indisputable, I kept thinking there either must be more to her than meets the eye or less to Bill. But Fleur stepped up nicely, didn't she? She took on Molly Weasley and survived, and she stood by her man, though his handsome looks, not to mention his entire future, may have been permanently damaged by Greyback's attack. Will Bill and Fleur make a contribution together, in their new role as a couple? Is there some usefulness to Fleur's Veela background that can help Harry in his cause? Or some magic about her particular wand with its unique Veela hair core?

5. Bill's wounds are unique. Even Lupin wasn't sure just what would happen to Bill, since Greyback attacked him outside of a full moon. Will anyone be able to help Bill? How much adjustment will he need to make? Will he have physical limitations? How will he react to the loss of his good looks? Will he suffer ongoing pain from his wounds? Will the full moon bring him any sort of transformation or discomfort? Will he lose confidence and begin to withdraw, as Lupin has? Or, might his wounds be a blessing: a means to heal others who have suffered the cursed wounds of a werewolf? Could help be on the way for someone like Remus?

6. What will Bill's professional life be like? How will the Goblins react to his new and unsettled status? The Goblins are unpredictable at best. They certainly do some shady dealing themselves, and don't seem too worried about propriety in general, but how will they react to Bill? Will his value as a successful employee weigh with them? Or might Bill find himself in a similar position to Remus - an outcast with a great deal of talent, brains and heart, and nowhere to offer it?

I think that the most probable contribution for Bill to make will be as a Curse Breaker in relation to the Horcruxes. How long will it take Harry to confide in him, when he is so determined to keep Dumbledore's counsel to himself? Will McGonagall hire him in the DADA position, and will Harry's trust of him grow at Hogwarts? That is, if Harry returns to Hogwarts with any regularity.