https://en.bitcoin.it/wiki/Mining_hardware_comparison
and put that hashrate into a profitability calculator here:
http://www.bitcoinx.com/profit/
It told me $0.20/day. However, the question I have is that when I entered 5000 mh/s (the 5 gh/s some companies are putting up for sale like bfl), it said that it would make $40/day, and bfl is only charging $274, so why can't you buy one of those systems, and make your money back in a week?
well, probably because they only exist in people's minds? the company will gladly take your money today in exchange for a promise to send you one of those sometime in the future. and a short while after those start delivering the difficulty will go up so that you don't make anymore than gpu's do now.