Grid power to our area comes via overhead wires through timbered country, and we lose power maybe a dozen times a year - sometimes due to planned maintenance or connecting a new consumer to the grid, but other times due trees/branches falling across the lines (and not just in storms either -Eucalypts are notorious for dropping branches on still calm days!)
End result? A generator/s pretty much an essential bit of kit if you want to keep fridges/freezers running, let alone just having lights, water pumps, watching tv etc.
We used to have a petrol-hungry 7kva "dirty" gennie which ran the whole house, aircon and all, but replaced that with two Honda 2kva "clean" output units. Economical, easy to carry around, can be paralleled to give 4kva. Very useful if I just need 240v on the farm somewhere to run a power tool.
Honda/Yamaha etc are the big name ones here, but more generic ones (cheapy Chinese) can be had for about a third the price.
As for fuel, our "standard" petrol is 91 octane unleaded. A workshop mate highly recommends adding a fuel preserver as soon as you get a drum home, and then it should be good for MUCH longer than not adding it!
EDIT: Honda/Yamaha etc - refers to the portable enclosed-in-neat-plastic-housing low output inverter gennies; re petrol (gas) - ULP 91 is UnLeadedPetrol without ethanol. E10 (with 10% ethanol) sells for 2 cents/litre less than straight ULP 91.