I was just thinking, which couple's character arc is doomed this season?

Oops, forgot to add 2 before posting! Doh!

Bernard & Rose

AND OF COURSE: Desmond & Penny

It seems rather silly to include Jack and Juliet and leave out Sawyer and Kate -- since neither are currently couple. Juliet is involved with Sawyer, not Jack in the same way Sawyer is involved with Juliet, not Kate. The Jacket romance burned out in one season; while the Skate relationship has been there for going on five and looks to be making a come back if Juliet is dying or leaving the Island as recent spoilers suggest.

Hard to say.

-Horace and Amy seem doomed to me, even without the fact that we know he dies in the Purge, so I voted for them.
-Juliet and Sawyer I don't believe will last, but it might last into the sixth season.
-Ben and Vincent were never a couple. Christian and Vincent, now...
-Jack and Kate I almost think is already over, but who knows?
-Juliet and Jack aren't currently together, as others mentioned. (But whoa! A lot of sparks between them).
-Polar bear and the smoke monster: Aren't a couple in the 70s, and I think all the polar bears are dead in 2008.

i don't think any of them are doomed. i think that jack and kate are making a comeback. they're always in sync in every finale.

I'm placing my bet on Jin and Sun

Although I am mostly JATER, I feel like Jack & Kate arc is coming to an end.