Ok, thanks. Those are really helpful answers for a noob.

So, neglecting the cost of hardware, what is the current cost, in joules, of digging a coin out of the cryptographic ground? I assume the answer will be a range of values; I'm interested in the variables.

Also, how do you guys measure your energy consumption?

it's 28 April 2011, mtgox is trading at ~1.75 usd/btc. I've been mining with a 3 GHz CPU for ~24 hours now. My client says it has 8 connections, 120606 blocks, and 1 transaction (my 0.05 from the faucet). How many alpaca socks can I buy?