ATLEAST 80Ghash.. as this week nets in about 0.1 a day. but then the next difficulty jump it would be a 120ghash, then 170Ghash

thats between 30-50% jump in hash requirements per 2 weeks..the cost of constant upgrading exceeds the income.

we are no longer in the gold spectre days of the wild west, now we are moving into the industrial and town settlement stages of the wild west. setting up shops, renting out rooms, selling beer in saloons all for the chance of getting miners income without the sweat and heat that comes with mining.

so buy a brand new xbox/ playstation. (price ticket of a few hundred dollars) and sell for a 10% price increase (but for bitcoins) then youll receive 0.1BTC profit if you sold one of them per day.

think of selling 10 items priced wholesale of $30 which u can sell for $33 worth of bitcoin .. again there's your 0.1BTC

retail is the way forward, unless you want to risk the next gen miner that comes out, hoping for a better ROI then the current 333mhash chips currently give you