I know Caleb will hate me for suggesting this
See if you can find a pair of used Cerwin Vega RE-20/RE-30 used. They pop up on craigslist every once and while, and can usually be found for $50-400 a pair.
They will sound better than any of the PA speakers in your $800 budget, and while they are technically "home-audio" they will easily keep up with a drum set and then some in a small room (they are stupid loud!).
Their crossover is also a pretty efficient design so any decent home stereo amp will drive them just fine; and if you ever do something stupid with them, they have fuses built in.
