Starbuck was a fucking angel?!?! What the hell.
Though giving up technology was the worst thing. First of all, that sucks. When they made this decision, I imagine that they just shot Doc Cottle. Second, what a vapid resolution to the series' theme! Ending the cycle of violence between humans and their mechanical creations is an interesting idea. But a substantive exploration of human (and hypothetical AI) nature, this was not. Hell, the two were hardly even linked!
And the very end of the series -- the scene in the modern day -- shows that abandoning technology was not the point. Or, at least, it wasn't a long term goal. So... what was the point?
I actually liked that last scene. Or, at least, I hated it a lot less than the rest. As an allegory, the message that the future is in our hands is kind of cool. But shouldn't that come with some kind of lesson about how to break the cycle of war? Ideas, anyone? The series finale fails both for me and on its own terms.
Mood-wise, I thought the most representative scene was Bill Adama telling the dead Laura Roslin about the cabin he's building. Humanity's vitality is gone, even though physically, it rambles on pointlessly and somewhat senilely.
One last note that isn't super pissed off. What was going on with "Earth" took me a while to figure out. The first Earth they found, which they sought for most of the series, was not our Earth. It's where the 13th tribe (the cylons) went and then nuked. Starbuck jumped Galactica to our Earth, which they hadn't been to before. They had a raptor on board, which jumped to the rendezvous point and brought the fleet back. And they found pre-humans that separately evolved to be genetically compatible... ok, super pissed again!
EDIT: I'm still trying to decide if the opera house visions paid off. You expected them to be metaphorical, and they were, but more than barely? The level on which they most closely correspond to events is the literal one. Athena, Roslin, Gaius, and Six were literally chasing Hera around.
But we expect this to be true on a more metaphorical level. Roslin is (or was) the President. Thus, we expect that when Gaius and Six take Hera from her and Athena, they are both taking her from her mother and also taking control of humanity's destiny from Roslin (and the rest of humanity). They are off to raise Hera and set a course for humanity. I can only sort of map events on this metaphorical level. Gaius makes a speech that (in part) gets Cavil to agree to a truce. Had he not brought Hera in there and made that speech, Galactica (and the future of humanity) probably would have been destroyed. But Gaius doesn't really control these events and the particular things he says don't even matter. Cavil taking Hera hostage etc etc etc is just a series of things that happen. So on this level, I don't think the opera house visions work.
Finally, what was the deal with the expressions that Saul and Ellen had in their last scene?
EDIT2: C notes that Hera being modern humanity's mitochondrial Eve means that most Galactica humans probably died out.