Tonks will always be my favorite Hufflepuff, but Dumbledore is definitely my favorite character. He's witty, wise, has some of the best lines in the book, and is also extremely flawed. It took me back a bit after reading the seventh book. I think I felt a lot like Harry - did I know this person at all? But it all completely makes sense. For someone to be as wise as Dumbledore, you'd have to go through some pretty life changing experiences. Dumbledore has his secrets and sometimes he's wrong, but I can't blame him for any of that.
On a side note, in honor of Harry's birthday, I dug out my Sorcerer's Stone game and started playing it. Hopefully, the youtube link will work by the time this is posted. http://www.youtube.com/watch?v=AE7Cw9vegkU