10 mysteries about Lost

I'm super-pumped about the new episode tomorrow night. With my excitement comes the requisite speculation, hours reading LostPedia, and all sorts of random conjecturing. I've come up with a list of 10 mysteries that need to get answered (and answered well) before the series ends, or I am going to be righteously pissed. Notice that I am not saying that all of these mysteries need to have a "good" explanation, some of them (like the mystery of the sickness) I fully expect to be explained away as having just been a hoax.

1. What the hell is special about Walt? And, an ancillary mystery: If he's so special, why has his character played such a minor (non-existent) role in the past few seasons?
2. What's the nature of the sickness, the vaccine, and the quarantine? Was any of it real or just a hoax? Relatedly, why do women seem to have such trouble giving birth on the island? Why does Danielle think that the sickeness is related to the monster (and, what the hell is the monster?)
   
3. What is the nature of the feud between Ben and Mr. Widmore? What are the "rules" between the two of them? Which one of them is the "good guy", and which is the "bad guy"?
4. Who are Jacob and Richard, what are their backgrounds, and what are their purposes? What is Christian Shephard's relationship with Jacob, and why is he used as a spokesperson for Jacob from among all the other dead people on the island? For that matter, so long as I am musing (and since we all saw Locke come back to life after his second plane crash), is Christian really dead?
5. The island seems to have it's own consciousness and it's own agenda. What is the nature of this? Is Jacob the persona that's acting on behalf of the island, or is it something else all together. To what end is the island acting?
   
6. What was the incident at the Swan station? For that matter, what is the purpose of the Swan station, and what is Radzinsky's relationship to it? How did turning the failsafe key make all the problems go away (and why didn't somebody turn the key sooner?)?
7. What makes Locke so special? We saw in the flashback that he failed the little test that Richard administered, so why is he still chosen to be the leader of the others? What does being their leader entail, and why the weird selection process?
8. What really lead up to the Purge? Why did some of the Dharma Initiative people (Ben, Ethan) join the others and choose to kill all their Dharma friends and relatives? If the Dharma Initiative was really trying to save the world, why would the Hostiles want to kill them all (and who will save the world now that they are gone, assuming the world really does need a'savin'?)
9. Why did the Oceanic 6 all need to return to the island? Locke putting the frozen wheel back on it's axis seemed to restore the flow of time and "saved" the people still on the island, so why did he have to do anything after that?
10. What is special about Desmond, and why don't the "rules" apply to him? What are he and Penny up to now? On a related matter, was Penny born on the island? How did she know so much about it (including how to look for magnetic disturbances to find it)?

There are a number of smaller mysteries that have been raised this season and that I expect will be answered shortly, so I haven't included them here. There are a few other issues that I wonder about, but that I don't think are as important, or that will probably be explained as part of a larger explanation of one of the things above (What is the statue, what is the temple, etc).