As I posted in
another thread, GPU mining is still very profitable with paid-off hardware.
-------------------------------
With an existing 5850 GPU and summer air conditioning, it is costing me ~$0.80/day to mine (total rig wattage). (~$5.60/week)
At the current difficulty, I earn ~0.09333BTC/week which is currently ~$12/week.
That makes for a profit margin of ~100+% and is significantly cheaper than purchasing BTC directly with that ~$5.60/week.
At the current difficulty, it would be profitable for me to mine even with the price all the way down at $61/BTC.
very true im mining at 1.9 gigs and i made over $300 after power costs and that's assuming btc price doesn't go up which it will.