I have a Behringer Eurolive B115D 1000 watt
That alone powers along very nicely. Great bang for the buck. At about half volume you can no long hear the sound of your sticks hitting the pads. At 3/4 power the kit moves a little when you hit the bass drum. I've never run it at full power but I suspect the kit would melt.
Under that when on stage I have a Behringer Eurolive VQ1500D sub woofer.
On stage I have my drums and my vocals coming out of the combo above. Having the sub really improves the bottom end sound of the kit (Addictive drums 2). And as it has a built in crossover, only the mids and highs are getting sent to the B115D above making it's job easier.
The sub is a little overkill admittedly and the B155D is plenty on it's own.