First, read this page, it is perfect for you:
kW is power, kWh is energy. People have daily kWh needs, not daily kW needs.
Thinking about it another way, kW is the rate (speed) at which energy is generated or consumed.
You may have specific power (kW) needs, for instance, if you want to turn on everything in your home at once, you will need a certain amount of power.
This is different than energy, however.
One last way to think about it, with numbers:
If you turned on two 1000 W space heaters at the same time and left them on for one hour, you would consume 2 kWh of energy. If you turned on one 1000 W space heater, left it on for an hour, turned it of, and then turned a second 1000 W space heater on for an hour, and then turned it off you would ALSO consume 2 kWh of energy. The difference is that in the first case you would need 2000 W of power delivered to your home while in the second case you would need only 1000 W.
I think you are asking about energy so I will talk about energy:
The average American household consumes 10,656 kWh of electrical energy per year. Dividing by 365 days: 29.2 kWh per day.
For $40k one can purchase a Bergey 10 kW (wind powered) generator. This would produce 240 kWh per day.
Note that wind power is not practical in all places due to weather, available space, and other factors. Furthermore, not everyone would choose to purchase a wind turbine with $40k.
Be prepared for backlash from people who know what "windmills" are. They are not used to generate power, they're used to grind things. Low speed and high torque is desired in a windmill while high speed and low torque are desired in wind turbines.
http://www.snopes.com/politics/business/gorehome.asp (this page includes Department of Energy references for average American energy usage).
http://www.abovetopsecret.com/forum/thread68751/pg1 (references a consumer-level wind turbine).