It's amazing that the mining hardware just keeps piling in --
Yes, but than again it is still profitable. I thought mining would be over by now, but it just does not want to give up.
My 8 miners acquired 3.5 BTC in the last 22 hours. Even at $10 per BTC, that is $35. My electricity max per box (4 PCs), is roughly $1 for the day, therefore $4 in total.
My stats are that I'm earning $17 a day (taking into account currency conversions and MtGox fees) but power costs $5 per day (measured, not just estimated from parts specs). Not everyone pays a few cents per kilowatt like US/Canadian citizens seem to do. With a 50% difficulty increase that'll be $12 per day but still burning $5 in power. Does it make sense to have $1000 of hardware producing less than $5 a day? (Don't forget taxes must be paid on income). Bitcoin's USD$ value did not increase at all in the last two difficulty increases, and there is no evidence this trend is about to change. MtGox's little adventure is unlikely to have a stimulating effect on speculators either.
I have a feeling many bitcoin users are piling in without giving regard to the cost of power (and the cost of cooling where required). Pretty soon they'll be thinking "free cash!" while spending $1.10 to make $1.