Nixxin claims to do 2700 M/s, after spending 1500 bucks in the setup. (however he claims to have 3 ATI 7970 GPU's, which in total can do 2000 M/s at MAX, so he is full of shit there..)
But, let's take his number of 2700, According to the calculator:
per Month ฿5.38 $621.36
And he claims to be from Canada, where electricity is fucking expensive.
So, he makes with luck between 400-500 per month.
You consider that a lot of "money" ?
With luck, if the bubble doesn't crash, he will recover the 1500 bucks in 3 months.
And, you must consider the difficult of mining gets harder each day.
So, make that 3.5-4 months... And then, if the bubble doesn't crash, he could make some bucks. LOL.