None of us know, but we all speculate, and even assume a bit. My question, what are the sides of the war (granting there really is a conflict coming).
(1) among the others (2) in ancient times among the ancients, whomever they are (3) between the island and outside forces, like the US Army? DI? (4) etc?
What I'm really posing here is partly a response to the idea that, for example, though we don't know what the war is, that "the others" will form a side. But as we've learned, Widmore is not some mainland industrialist that got wind of the island, he IS (was) an other. Forget the was because Ben "is" and other but no longer the leader and Jacob said "help me" to Locke. Don't know why, but it implied to me that Jacob is not all that together with Ben, and of course Christian was more explicit about that. So the war might be between the others... even DI, with the Widmore links may simply be an outgrowth of one of the factions.
I can't answer my own question, of course, but I hope the conflict takes us further back in time to the ancients, and the struggle is an ancient one with lots of consequences that will be explained as "whatever happened happened" is clarified (possibly starting tonight). But I suspect everyone of interest may make it to 2008 (or 7 or 9 or ...) and the conflict will be in present time there. I think it makes more sense to have it be in history, but depending on how the details of Lost time travel and change works out.
Also, do you think it will be a two sided war, or more... I'm voting three right now, maybe four... Widmore, Ben, Bram's People, and Richard as the only one really representing the others for the long term (aka "forever").