I have not seen any confirmation yet (not even in the 8 hours of game play I watched) that confirmed this question. I am wondering if the main quest is a completely different story line than the civil war. Are we allowed to just be Dovahkiin and fight off Alduin without getting involved in Skyrim's political mess?

I ask this because having the main quest be completely separate from the Legion/Stormcloak story line would offer even more quest lines than if the civil war and main quest were intertwined.

Hard to tell, considering you don't seem to join them in the main quest. As an example, the Stormcloaks only seem to ask you to join if they see you cast a certain spell.

I think you have to choose a side, but may not have to actually join them.

There's an achievement named "Diplomatic Immunity" that is grouped with the other Main Quest achievements in the achievement list. I believe this means that at one point in the Main Quest, we will achieve Diplomatic Immunity and the Stormcloaks and the Legion will leave us alone while we go about doing our business as Dovahkiin. If this is true, then you probably don't need to join them in the Main Quest.

Or, possibly, you'll have to solve a certain number of quests for both of them which will help reach a truce or a cold war style of situation while the Dovakin takes care of the Alduin problem.

Could be, but if those quests you have to solve are the ones listed as achievements, I doubt there will be a cold war since the capital of one faction will be conquered by the other faction.

Unless the conquering of the city only happens if you actually join a side. I don't know if anything says that that is a main quest achievement or a faction achievement.

Yes that's why I said "but if those quests you have to solve are the ones listed as achievements" in response to "Or, possibly, you'll have to solve a certain number of quests for both of them". If the quests that you have to solve are those in the achievements, then you will have to pick a side and conquer a city. If not, you might not have to. We also don't know if we even need to solve quests for both of them anyway.

Ahh.. I'm half-asleep.. Heh...