Short answer: 20-50lbs per hive in south east Wisconsin.
Long answer, my tale:
Well my rookie year I harvested 100lbs total from the 2 hives. And the trade-off was that the bees didn't make it through the winter. Although the true cause was freezing before they actually ran out of food, but they would have starved before spring. That year in Wisconsin beekeeper a on average lost 45% percent of their hives over winter. It was a terrible one for bees.
Year 2 I aimed to get my bees through the winter. I started with 4, but soon combined 2 of them; one was a little weak and the other had a laying worker. I only took about 10 frames total among the 3 hives remaining. I wrapped the hives for winter and still lost them all. One made it through, and I was feeding it. But in April it swarmed and left without notice or queen cells.
So year 3 and disgruntled, I decided I'd take more honey. I started with 5 hives and reduced to 4 during the season, combining 2 weaker hives. It was a banner year. I harvested 200 lbs. in late July, early enough for them to build up more winter stores, and still left a super on 2 of them for added food. All 4 made it through the winter, but I was already in China. The spring was long and wet into May, and without me there to feed them to get them through they struggled. As I would visit home once every 2 months I'd combine weak ones until there was only 1 remaining in the fall of 2011.
At a small scale of 1 or 2 hives it would be cheaper to find the local club and inquire who has bulk honey to sell. But if your not doing it to save money, then it's a great hobby. I bottled mine and sold it at work for $5/pound which offset some of the costs. Another 100-200 pound year and I probably would have paid off my equipment and it would be paying for itself.
That and my garden/orchard are the 2 thing I miss the most due to living in China now. So brewing gets all my spare attention.