When my band started out we went with a new pair of Peavey 8 ohm TL 5X 15" speakers and a powered mixer which puts out 200 watts/channel into 8 ohms. We also use a pair of powered 15" Carvin speakers for monitors. We have played small rooms, biggish rooms, at the D.C. Convention Center, and outdoors, and find that 200 watts for each Peavey speaker really isn't enough. In more demanding environments, like outdoors, or in a room with a fair amont of background/crowd noise and lots of people who absorb sound waves, the power amps in the mixer have occasionally shut down from thermal overload. We've started to use the Carvins as FOH, but now sometimes find ourselves with inadequate volume from the Peaveys in floor monitor mode. We don't play all that loudly (classic rock), but in retrospect I wish we had gone for a higher-powered mixer. We'll probably upgrade soon, perhaps to a A&H unit which puts out 500 watts/channel into 8 ohms, the most I've found so far in a all-in-one solution. So, if you can possibly swing it, I'd recommend going with more power from the outset - you really can't have too much, but you definitely can have too little, especially if your band finds itself gigging in larger venues or outdoors!
