I also went with a 5 kw diesel generator. It powers my whole house without any difficulty, and I'm on well and septic. The only thing I don't run is my electric dryer. Diesel fuel is more stable and less dangerous to store and it can be stored much longer than gasoline.
Total cost for me was $1650.00...$1100 for the generator at Costco, $400 for the transfer switch and $150 to have it installed. Generator is stored in my garage and wheeled out when the power goes out. It's a quiet-run unit that I can't even hear in the house. I also have battery-backup for the computer and TV.
Ping
I have three gennies, one I picked up by accident, its an old military 30kw three phase powerplant from the late 50’s, has a Continental gas six cylinder engine, its just sitting in my back yard, then I was given a 5kw portable gas gennie but it needs a new carb, and then some years ago a new employee on his way up the Alaska highway found a slightly battered 12kw Onan diesel genset along the road, like it fell off a trailer.
I bought it and some other items like a welder and an air compressor from him for $150, a couple months later he demanded the gennie back after he realized what it was worth, I had to weld up a crack in the oil pan and a bent filter housing, I made a skid frame for it and its in a small utility trailer at work, runs great and has low hours.
The concrete batch plant where I work at in Alaska many yuears ago soley depended upon generators to provide power for the heavy equipment, this was before they put in a high voltage line and transformer, so I have spent many a year starting gennies way up to a 150kw with a 8v71 Detroit diesel. We still have all the big units just sitting around and in working order, all are 3 phase though.
The Onan uses just a bit less than a gallon an hour. My setup at home will be a dual gennie affair, a fuel sipping one for most of the time and for just a couple of hours the big unit to do any heavy load work, or to eventually fast charge a large bank of batteries when no sun. And getting a natural gas kit is also on my shopping list, not for just gas because in a major earthquake most likely the gas line will be gone. But its cheaper to use natural gas.