in reality, a decent income is one that buys you all the neccesities you need to survive and afford to have a roof over your head/food on your table. In some locations, that can be $1,000 a month (detroit, anyone? :D ). In order locations, that can mean $4,000 a month (vancouver, la, new york, etc etc)
Of course if you're a consumer whore (and who isnt these days), then the more, the better
