Ermmm guys... Am I doing my math right here?
According to what I'm reading here and the following parameters:

6x R9 280x (alledgedly they should hash @ 550Kh/s each?) = 3.3 Mh/s
Current difficulty: ~6.5
Block Reward: 50
UTC/BTC rate: ~ 0.00033
BTC/USD rate: ~ 640

...would make me over $100/day !?

I somehow doubt this is correct...