Well I expect this match to be a real "show stopper". Those two guys are both able to deliver very good matches, they've been involved in a very good feud all this year, and this time it's for the World Title too; now the spotlight is solely on them. I believe it has been really a long time since a World Title match was so meaningful, as there was more than just a more or less "random" feud behind it. I think it is a good thing WWE are exploiting this great feud to this extent.
As for the outcome, I see two options... The logical conclusion is that Jericho goes over HBK here; firstly because we all know HBK does not need or want a title that much, since he's on limited schedule anyway, and secondly, with the feud already nearing its end, it can serve to give Jericho a high-profile title defense (especially over HBK in "his" match) without having to sacrifice any of the more reasonable challengers right now (Batista, Cena, Punk) in order to establish Jericho as a more credible champion.
However, there of course is the fact that by all means, HBK definitely deserves another World Title win without question, and with WWE trying to surprise people more often lately, HBK might just pull out the victory here... And then Jericho could exercise his rematch-clause at the Series, culimating in a Last Man Standing or something, where he reclaims the belt from Shawn, and is open to other challengers...
I think I'll go with Jericho winning though, as it will be the best for him. HBK, even if he deserves it, does not need another title - besides, if he wins another one, it should probably be at WM; but Jericho is definitely being built up as one of the main heels for the years to come, next to Orton and Edge, and he needs to be taken seriously. His feud with Michaels has already done much for that, but if he goes over HBK in a ladder match, it will mean that much more.
But in any case, I think we are in for a tremendous match that will go back and forth and should finish with a great conclusion.