First off spend the most you can...
Avoid cheap china 2 / 4 stroke units (been there done that)
buy a honda
Buy a Honda
BUY A HONDA (with a branded generator coil) Paramac or similar....
ok errrr
Cheap china 2 stroke ... i erm overloaded it (not intentionally the power drill i was using was in its upper limit but under load it took more power and took the coil windings and it then no longer produced electricity....
Cheap china 4 stroke was a bugger to start then ultimately despite been very careful about overloading it the stator coil went within about 24 hours absolute maximum use and again no power.....
I bought a second hand "site" generator of a contractor i know (he had gone up to a bigger diesel unit so was selling) its been abused but looked after and it starts first pull 95% of the time.....
this is it:
http://www.elliotts4tools.co.uk/Pramac- ... p-149-676/
but just looks more battered

and it will run a 9" angle grinder (those who dont know these take a lot of power at start up)
If you want silent err save about a grand but that will only get you 1.6kw continous (be very wary of generators stating "2000w" ensure thats running and not start up some cheaper ones the start up current can be twice the actual running rating)
http://www.seddondirect.co.uk/honda-eu2 ... wwodeTcNbw
watch the lookalike generators
http://www.tool-net.co.uk/p-347966/clar ... wwodhrAHzA
the noise levels vary obviously but so does the testing distance and "load" eg how fast its running depending on what you have plugged in
Least Honda has a established spares and service network too...
If your planning on running sensitive stuff look for atleast a AVR (auto volt regulator) or Inverter pure sine wave based technology)
Oh and without a petrol licence you can only store 30 litres in approved cans at home... (fuel in use doens't count eg fuel in generator tank / car / lawnmower
Also modern petrol contains bio ethanol which attracts moisture so a fuel stabliliser is a worthy investment to protect the carburettor / fuel system if its not regularly run........
mate of mine whos a farmer also swears by a shot of Red-x in the fuel and ive had no issues since adding both.....