No, the exchange rate ($2.6/BTC) has still not fallen under the cost of mining for the average miner who selects the right GPUs ($1.8/BTC). The current difficu

No, the exchange rate ($2.6/BTC) has still not fallen under the cost of mining for the average miner who selects the right GPUs ($1.8/BTC). The current difficulty is 1468e3. It takes 2^32 * 1468e3 Bitcoin hashes to solve a block of 50 BTC. The majority of people mine with HD 5000 or 6000 series. If you pick efficient ones, you can count on 2 Mhash per Joule. The average worldwide domestic electricity price is $.10/kWh. So the average cost of production is: 2^32 * 1468e3 / 50 (BTC per block) / 2e6 (Mhash/Joule) / 3.6e6 (Joule/kWh) * .10 ($/kWh) = $1.8/BTC