1. Add me to the "Snape is not evil bandwagon." Dumbledore trusted him completely. He had to have a reason - perhaps they made an unbreakable vow. I think he was trying to advise Harry, even at the end. I also believe Snape loved (loves) Lily.
2. Dumbledore is not just mostly dead, he's all dead. But in the tradition of Gandalf, Aslan, Obi-Wan and Jesus, his death will have a greater meaning, a more powerful presence than if he were bodily alive. His patronus is a Phoenix, after all.
3. Much has been made of Voldemort's and Harry's wands being sister wands, having been made with Fawkes' feathers. (Does anyone else find a Phoenix named Fawkes a real groaner?) I would like to add Harry's wand to the list of possible horcruxes. TellTaleOrange already added Voldemort's. This theory could support either wand. . . .
4. However, I think it makes sense that an item from each house be a horcrux, as they would all link to the school. I could see Voldemort attaching that signifigance to each item he collected. My other guess is that Nagini is not a Horcrux, but 5 & 6 are a Gryffindor item and a Ravenclaw item. The sword and ..... something. It will be a long 2 years until the last book comes out. I will be rereading the series to refresh my memory. If I find any mention of a Ravenclaw item, I'll let post it.
5. Interesting how Voldemort's and Harry's life stories are so similar. Sort of a whole "two sides of the same coin" thing going on.