Where do you live and ride? If it's in Florida or a similar flat area then a double should be adequate. If it's in a very hilly area (I'm in Pittsburgh where hills are unavoidable and steep hills are common) go for a triple.

How young and strong are you? My son-in-law is a very strong competitive rider. For him a compact double is plenty for the hardest ride. For me, who is neither young or particularly strong, a triple is the only way to go.

The "complications" of a triple are way overstated and they are no more difficult to use than a double. If you don't need the granny just don't shift into it.