I hear that Meijers is cheap if you live near one (I don't.) Target (the ones that have a grocery section) usually has a good price, but all their organic brands are ultrapasteurized (my kids won't drink ultrapasteurized milk.) And I noticed that one of the discount grocers - Ultra Foods maybe? - had organic gallons in their last sales flyer, which surprised me to see. So maybe there will be some competition in the organic area - would be nice.
Jewel definitely has the highest prices on milk, unless they are having a sale. We used to buy Oberweiss, but we go through so much milk (2 boys - about a gallon every 2 days) and it's hard to keep hunting down the good deals and in the brands they will drink. Mostly I buy the brands without artificial hormones lately (costco, dean foods) and hope for the best. But you're right to buy organic - they say it's one of the most important products to buy organic if you can.