Used to use a 4kw portable gasoline generator with extension cords to run fridge, a couple of light circuits, computer (ignore the "sensitive electronic equipment" warning IME), well pump, and (propane) furnace. Then came the winter of '09-'11, immediately after which I installed a 10kw Generac (I just turned 70 and not only did I get tired of slogging through the snow to set up, and then fuel the little genset, I had just had rotator cuff surgery and wasn't supposed to move my left arm. Right.)
We have had several outages since the install, the latest the result of the derecho of the past weekend (a tree in our front yard totalled my wife's Honda, general carnage all over the farm), and our Generac performed flawlessly from lights out Friday evening until restoration of power yesterday afternoon.
My installation included having a buried 500 gal. propane tank replace two 125 gal. standups (no charge from the fuel company for the upgrade), and a transfer switch (included with the Generac) that I installed myself. It controls all circuits in the house except the shop (90A subpanel), and I am very pleased with it. The auto test every Sunday morning is music to my ears, and I love lifting the cover to read "Ready to Run" on the LCD readout.
My recommendations to the OP based on the above experiences are: 1. go whole house, it is not much more money, but a much easier install. One way to save money is to use a load shedding transfer switch, which does just that- if the load rises above a certain percentage of the generator's output, it selectively shuts off some circuits; 2. get a sufficiently large propane tank, if that is your fuel choice; 3. have it installed professionally. I did it myself, but I would not recommend it. For example, in the case of the Generac (Siemens) switch, it did not have sufficiently flexible knockouts to accommodate my installation requirements easily.
The downside of this project is that once done, your friends will come over for showers, bringing coolers full of food to store in your fridge. The upside- humorous discussions with the wife saying, "we gotta get one of these," and the husband saying, "I can't see that for only a few days of minor inconvenience." Those husbands are generally not the types who are members here.
The very best thing is the first time the lights go out, and your wife says, "what now?" and you just calmly reply, "count to fifteen..."
Good Luck!