Well, I think they tied up a few of the loose ends.

They suggested what caused the airliner to crash, if it was magnetic it would also explain how the drug plane got there, they explained how Desmond came to be there and what he's been doing since he ran off from the hatch, and they gave some more background on Libby/Elizabeth, told us who the leader of the Others was (Henry), and gave the course direction for getting away from the island.

And they introduced a new character (Widmore) for next season.

Oh...yeah...I almost forgot. We also got to find out what happens when you don't push the button.

__________________
charlie98210
"Whoa!" she said. "Cry 'Havoc!' And let loose the dogs of war!"
And, like Banquo's ghost, they just won't go away.