I am in New Zealand, where they now sell by the box Saints Sauvignon Blanc from the Marlborough. It's $20/1.5L, which is not actually any cheaper than the same drop bought in the bottle, BUT I buy it because I only drink a box per month, it keeps better and is more convenient.
(Plus I get a kick out of pouring myself wine from the box standing there with the fridge door open. I could be ... Roseanne! Or, you know, back at uni.)
MMM mentioned I think Banrock Station from Australia, which is also available here in NZ on a limited basis. From memory I think that was ok. I think the Banrock reds were better than the whites.