As a committed lazivore, I've always loved the idea of no dig gardening. It requires minimal labor. It allows natural systems to do the work for you. And it avoids many of the evils of industrialized food production—most notably soil compaction and the exposure of soil organisms to the elements.
Other hardcore sustainable gardeners take a different approach however. Most notably, the biointensive method of gardening recommends double digging garden beds to break up both top soil and subsoil, and then working in large amounts of organic matter. It's a technique that, proponents claim, can result in huge amounts of food being grown on relatively tiny plots. In fact, says Robin Mankey of the Grow Biointensive demonstration garden in Palo Alto, it is possible to grow most of your diet on about one tenth of an acre of land.