Until March 31, 2012, you get 5% back on utilities.
Where I live in Brooklyn, NY, I normally would not pay my natural gas (National Grid) and electric (ConEd) bills by credit card because there is a fee of $2.25 and $4.75, respectively. But if you charge a large amount, the fee ends up a very low percentage of your payment. The payment (and fee) is collected by a third party payment processor, so I suspect you may be able to pay more than your bill amount because they probably don't know how much you owe at the time they accept your payment. For National Grid, there is a maximum payment amount of $600 (but I suppose you could charge the maximum more than once and pay the fee each time).
It may be worth it to prepay for as much natural gas and electricity as you could afford to lay out money for in order to collect this bonus, which far exceeds the fees or any interest you would earn keeping the money in a savings account. And for those of you who just got the card recently, this is a quick way to meet the $1000 spending requirement to get your extra $200 cash back. Don't exceed the amount you will be able to pay in full to Citi when the credit card bill is due because the interest on this card is high.
By the way, I received this 5% bonus last month for paying an AT&T wireless bill, so now I know that AT&T wireless counts as a utility for this purpose.
