What would be the best laptop speakers for presentations and groups of people up to 60?

In my office we do training and host events. Usually we go to places that provide their own speaker systems. However, sometimes we find we need a speaker system for something like a DVD played from the laptop (pc). I was looking into getting speakers that are loud enough without being distorted for maximum of 60 people, in a bigger/wide room. They don't have to be superb quality, just easy to transport, setup and hear. If anyone can think of a system that would be great.