All depends on your budget, I've got a little 1.5/2kw one from tractor supply, weighs 30 pounds, 3hp engine ($120 on sale) . 5.5/6.5kw husky, 80-100 pounds from someone who 'broke' it just needed the right oil and gas ($80) 6kw winpower 'fire service' 220 pounds, and a 16/22kw genrac that lives in its corner of a shed next to its 'transfer' plug at my folks place ($850 used). Realistically, if your house uses gas for heating air,water and food, and you have city water or a shallow well pump, 5kw will run your whole house happily with a touch of common sense applied.
While doing an all day generator run at my folks with the big generac, took half a minute to realize why my air compressor sounded funny, its a 100 amp startup load and 22 amp 240 run. Luckily shut it off within about 5-10 seconds. The main reason for the big generac is that it has a 15 gallon fuel tank and at normal loads, it'll run about 24 hours.
for portable power, either the 2kw TS one or the 1kw truck inverter is da bomb. One quick note on the small 'import' generators, it seems they don't get cleaned during engine assembly, I'd suggest a 1/2 hour no load run, then change the oil, if it looks a little silvery or in my case like anti-sieze grease with grit, repeat with a 1 hour 1/2 load run, change, 2-3 hour half load run, change, then 4-5 hours at near full load, make sure its got great air circulation as the alternator will be cranking out a ton of heat. Do this until when you drain the oil, you don't see anything but oil. After that it was put in service and used for a full week and the oil was still clear. There was a lot of reports on this model of early engine failure, I can see why with all that junk inside it, and it only holds 1/2 quart of oil, but expending a gallon or two of good truck oil on breaking an engine in seems like a good investment.
