My life ended when Sirius Black died. I was in the fifth grade when I finished the book, and until that dreaded chapter I was convinced of my future as Sirius' wife. *sigh* Alas, all good things must come to an end. But, when I fixed my eyes on that horrid page, I simply could not read any more, and tossed the book to the side as I ambled down the stairs, blubbering. I threw my arms around my mother (who, coincidentally, is a Potter freak as well, so she understands the pain) and sobbed into her shoulder as I explained. All that I can remember about the rest of the fifth book is that Dumbledore does something to save Harry... Again. Everything following his death was too much of a blur for me, and now I feel that I can finally admit to my geeky reaction because I am in the presence of people who think the same way!
...Mom's cookies helped soothe my pain, by the way... Don't they always? ^^
I'm all about Snape. Easily the best character written in the entire serious (in my opinion). I was upset with Sirius, but not because I liked him. You could tell that despite his amiable qualities, he was still a total douche to people he didn't like personally. I was upset (at the time, but not with subsequent books) because I thought that any chance of exciting early chapters had died with him. Obviously I was proven wrong, but I thought that if it was revealed that Sirius was a good guy at the end of OotP then Harry would live with him then I could say goodbye to three chapters of every book being filled with Harry getting yelled at by is uncle.
Also, I think that we should all bow our heads in respect for the noble sacrifice made by Hedwig and the Firebolt in the name of filling potential plot holes.