Originally Posted by Deathmetalconga
I have a PA system, a pair of JBL EON-15 inch powered speakers. They aren't the cheapest or the lightest (15 inches, 45 pounds, 300 watts each) but they will swallow an entire band and then some with excellent quality. Amazing headroom. Now is the time to find great cheap gear on Craigslist so go for it.
You are right in getting powered speakers. Hassling with an amp and cables isn't worth it.
If you have a whole band, I wouldn't recommend anything smaller than 15 inch speakers. Sorry, but a full band needs a full system. Plus, you can always go with one speaker for smaller gigs.
JBL make quality gear. Although I have no experience with the system DMC describes, it sounds like a sensible solution.