I have an old 1986 Dometic portable generator my parents gave me. It is only 2250 watts, but does all i need for my house in a power outage. I don't use it camping as i always have electric to keep the wife happy.
I have powered the following at one time during our last power outage a couple of winters ago. I don't want to power my whole house, just the items that were necessity in my mind. Never had a problem with it.
Furnace (gas, so only had to run the blower)
Refrigerator
small chest freezer
two lamps
television
satellite box
internet modem
So what I am saying is simply to follow what everyone here is telling you, figure out what you need to power at home and size accordingly. As you can see i can get by with a small one since i have no need to power my whole house.