Like everything else, it's dependant on what you want to spend.
I have a new Yamaha ef2400is(hc). This is thier newer inverter-based 2400is that has some capacitors to start loads such as those found in a travel trailer's a/c system (the HC is High Current). Supposedly, it's good for 3000W for brief periods of time accordingly. It is larger and heavier than the "suitcase" 2000's of both Yamaha and Honda of course, but it's still super quiet and fuel efficient.
Unlike many who wind up getting bigger generators after buying too small at first, I got rid of a nice Ridgid 6800/9500W full size generator (which with a Yamaha engine worked great) to go smaller, quieter and more fuel efficient.
C-