The click together jobs are probably not powerful enough for the task you describe, as they are only about 150 watts total. We have a Carlsbro Traveller for small gigs; it's ok, but not enough punch for a large noisy pub. We also have a HK Audio LUCAS system. 600 watts, loud, very portable and fantastic quality. The amps are built into the bass bin, and there are two small satellite mid/treble units. All you need is a decent mixer, preferably with built-in effects, and away you go. Not cheap, although they do come up for sale on ebay from time to time at reasonable prices. These systems are built in Germany, and are very reliable and simple to use. They come in several sizes, from about 350 watts up to 2000 watts. The whole thing packs together, and is on wheels. Hope this helps.
Tim from Bit on the Side