Okay, just went for the family walk of the evening, and of course, we discussed nothing but Harry Potter.
A few more theories for you:
1) Fawkes: My mom and I are in agreement that the whole Phoenix re-birth thing is a big deal. Dumbledore burst into flames at the end at his funeral. I have a feeling this isn't typical for a wizard funeral. We're thinking that Dumbledore is either a. reborn, b. turns into a phoenix, or c. is joined wherever he is by Fawkes. Harry saw a phoenix fly overhead; do we know that that's Fawkes? Also, might Fawkes BE Dumbledore??? I know Dumbledore will help out Harry in some way...
2) Dumbledore's family line: Supposedly on mugglenet.com (i haven't been there yet) there is an interview with JKR, where she states people need to pay attention to Dumbledore's family line. He has a brother that has been mentioned before in the books... (I missed that! :must re-read

. There may be a Dumbledore-Harry-Gryffindor relationship somewhere. In all of Dumbledore's names, I couldn't find a "Potter" or "Riddle"...
3) Harry or Harry's scar as final horcrux: I don't think Harry is. I think Harry's scar might be the final horcrux. If it is, how will he destroy Voldemort? He'd have to destroy all the other Horcruxes, destroy Voldemort's body, and then kill himself. I'm not sure if JKR would do that though, it seems deep. But I wouldn't put anything past JKR.
4) Snape (again): I was reading a previous post where the person had a theory about Snape looking on Harry as the son he never had. I think that that is actually right. I also believe Snape and Dumbledore had some sort of agreement.
I also think Sirius is finally gone, for good.