I expected Tigh to die too. Which would be really unfortunate since he's been my favorite character (or at least in the top 3) since Season 3.

Did you see that little device that someone was pointing at the piece of dirt Adama picked up? And hear the little clicky noises it made?
That's a radiation detector, you can see a demonstration of some real world ones here.

I theorize that it's all about "all of this has happened before and all of this has happened again"
The people of Kobol destroyed themselves almost utterly in a war - they worshiped The Lords of Kobol who were Cylon-like beings. They didn't age but they were mortal.
Eventually the Lords of Kobol develop resurrection technology or something else wonky happens. This leads to a war. Kobol is devastated and the Lords of Kobol are killed in the process. Twelve Tribes go one way, the Thirteenth Tribe goes to Earth.
The Thirteenth Tribe destroys themselves. Irradiating Earth.
Kobol eventually recovers and is able to support life again.
The Twelve Tribes develop Cylons who eventually destroy them.
The Twelve Tribes exodus to Kobol and then to Earth.
The Twelve Tribes ally with the Cylons and declare an end to aggression upon the realization that all other roads lead to death.
The Twelve Tribes settle with the Cylons on Kobol after learning the lessons of Earth.
The Cylons are eventually worshiped due to their eternal youth, as the new Lords of Kobol.
Earth and the Twelve Worlds recover and are able to support life again.
War ravages Kobol and the Lords of Kobol are destroyed. The people of Kobol exodus to the Twelve Worlds and Earth.
Cycle continues to repeat.
Earth's role is to allow the humans and the Lords of Kobol to find peace after the war portion of the cycle.

I just finished the episode in which Starbuck's Viper is plummeting to some planet and she ejects her seat.

Finally gave into fan pressure - or finally took up the bravery to do what they'd hinted at all along and revealed Gaeta as gay (or at least bisexual I suppose).

Decent ending - although mostly expected.
Roslin/Adama scenes were good.

I don't buy everyone leaving their stuff behind in space. I have the feeling it would go more like:
Lee: "Like, yeaaaah man. We need a fresh start."
Everyone Else: "Shut the frak up, Lee."

I liked that the let Helo live.
I liked that Cavil got a "Darth Vader" moment walking down the halls with his Centurions shooting everyone.
I liked that they DIDN'T end it with a lame rehash of the lame Matrix Revolutions ending.

I would have vastly preferred if they had ended the series with Adama sitting next to Roslin's grave. The last scene was pretty lame and anyone who's been paying any attention didn't need to see it.

And really. Do they even realize that they basically implied that everyone dies except for Hera - and then she spends the rest of her life living with early tribal humans? Guh.

I thought the Adama/Roslin scenes were the best, like, it was totally expected that she would die but when it actually happened it was very sad. I loved the way they let her go, she died peacefully with Adama but it was very sad because the Roslin/Adama theme just always makes me cry. >_>

I didn't like that people were cool with the tribal idea, I would not want to be in that group. It was interesting how they did the Kara thing, it was a very Joss Whedon type thing to do. Sucks for lee to have to lose those important to him and spend the rest of his time figuring out what to do on a planet where you're just starting over.

Bottom jokes explained:
Erich von Däniken is the guy with the theory that aliens seeded the Earth.
I guess Adama killed the flamingos?
"Starbuck"s vanishes

In the final episode, the fleet of ships arrives at Earth - 150,000 years in our past.

They get rid of most of their ships - but that one on the magazine cover got left behind. In a bit of a plot hole (albeit a tiny one).

In the very last scene of the show, they skip ahead to present day Earth. They show a guy reading a National Geographic book about "Mitochondrial Eve" - the mother of all modern humans. And it's implied (explicitly stated, actually) that it was one of the characters from the show.

In other words, we're all aliens (and part robot to boot!)

The joke here is that who the frak would care about that if they dug up a spaceship right next to her?

The "Starbucks vanishes" joke is about the fact that one of the main characters ("Starbuck") was implied to be a supernatural being and simply vanished shortly after they reached Earth.