Ease, yes. Efficiency, especially the amount of the wafer that's wasted due to it being circular initially, not so much.
A triangular layout probably would be ideal - you could (or at least, should be able to) adapt existing equipment (instead of two cuts at right angles, you make three cuts at 60-degree angles - hexagonal layouts would require either piecing together triangles produced this way, casting much smaller ingots such that it's one chip per wafer, or stamping out the hexagons), and you reduce waste somewhat (depending on the size of the chip and the size of the initial wafer).
However, the problem with triangular layouts (and hexagonal, for that matter) is that it involves cutting along planes the original ingot (which is a single huge silicon crystal) won't naturally fracture in.
So... unfortunately, we're stuck with square chips (if we start building up 3D chips, we'll have the option of cubes and octahedra) because of nature.