3 x 7950s = 1800 kh/s which is $584.92 / month according to the table at
http://dustcoin.com/miningseems profitable to me, am I missing something?
Careful... at this very moment, DustCoin is using the Mt. Gox figure for BTC ($123.40), which is frozen since they halted trading. BTC-e has it at $84, Vircurex at around $90.
(still, that's closer to $426.60, which isn't awful)