God knows why I am doing this since my free time has become very limited of late, but I've been skimming through the books looking at everything Dumbledore said and did. Here are some quotes I found that now (for me at least, and perhaps for some of you as well) have another layer of meaning added to them since the release of DH and certain subsequent revelations.
"It does not do to dwell on dreams and forget to live, remember that." (PS:12)
"[H]umans do have a knack of choosing precisely those things which are worst for them." (PS:17)
"The truth [...] is a beautiful and terrible thing, and should therefore be treated with great caution." (PS:17)
"It takes a great deal of bravery to stand up to our enemies, but just as much to stand up to our friends." (PS:17)
"It is our choices, Harry, that show what we truly are, far more than our abilities." (CoS:18)
"The consequences of our actions are always so complicated, so diverse, that predicting the future is a very difficult business indeed..." (PoA:22)
"You think the dead we have loved ever truly leave us?" (PoA:22)
"My own brother, Aberforth, was prosecuted for practicing inappropriate charms on a goat. It was all over the papers, but did Aberforth hide? No, he did not! He held his head high and went about his business as usual! Of course, I'm not entirely sure he can read, so that may not have been bravery..." (GoF:24)
Note: The first time I read this quotation of course I found it really funny. But now that I know the reasons behind Aberforth's lack of education, it seems sort of heartless of Dumbledore to be making a joke at his brother's expense about it.
"Curiosity is not a sin [...] But we should exercise caution with our curiosity..." (GoF:30)
"[Frank and Alice Longbottom] were tortured for information about Voldemort's whereabouts after he lost his powers, as you heard."
"So they're dead?" said Harry quietly.
"No," said Dumbledore, his voice full of a bitterness Harry had never heard there before. "They are insane." (GoF:30)
"Understanding is the first step to acceptance, and only with acceptance can there be recovery." (GoF:35)
"If I thought I could help you [...] by putting you into an enchanted sleep, and allowing you to postpone the moment when you would have to think about what has happened tonight, I would do it. But I know better. Numbing the pain for a while will make it worse when you finally feel it." (GoF:36)
"No spell can reawaken the dead," said Dumbledore heavily. (GoF:36)
"You place too much importance, and you always have done, on the so-called purity of blood! You fail to recognise that it matters not what someone was born, but what they grow to be!" (GoF:36)
"Remember, if the time should come when you have to make a choice between what is right, and what is easy..." (GoF:37)
Sleepy now; will find more tomorrow....