The only costs I have is the orginal price of the hardware, then the electricity. Hardware will last for 10+ years, life time warranty, so after card death, I get a new gaming card (obviously ATI won't have any 6870s in stock then, so free amazing card FTW?
I live pretty near to renewable energy sources (dam+windmills), so my electric rates are cheap.
Currently they are $0.072
If I upgraded my connection to commercial AND used over 10,000 KwH, it'd only be $0.048..which is what? 1/4 the national average?
Doing some math now, it takes about 1 kilowatt to produce 1 gigahash (the power usage is including cooling and other factors).
Let's say it takes 1 week at 1 gigahash to produce 1 bitcoin, going 24/7...that's 12.096 USD in electricty.. I mean, seriously, I'd almost DOUBLE my money in a week from electricity, from doing NOTHING. Sure, I paid for hardware, but that was a single payment, it'll make it back in a few months.