My own rule of thumb.... the inexpensive ones with Briggs/Tecumseh/Kohler engines will do just fine but are very thirsty. Honda will run about 1.5x as long on same amount of fuel, diesel about 2x as long (+ if you heat with oil you have a huge reserve). I run a Yanmar 3700 diesel, does everything you listed, but on a staggered start. Air compressor with lights only. Forget the dryer, washing machine is probably around 1/2 hp.
Make sure you have enough generator to handle the STARTING load combined with the running load of any other items that are on. You don't want to burn out a submersible pump because of low voltage.
http://www.genexusa.com/wattage.html