OK, here's how I achieve this shot. No bulls**t, I was quite surprised about the results myself too!
This photo is not PSed, only minor adjustment on contrast and brightness + some USM. Other than that, nothing's manipulated.
What I did was place all the items on my marble floor at home, place the 580EX on the left of my camera and use the ST-E2 to bounce off the white ceiling. This is the result I got! What I can think of is because marble is porous, so it can absorb and reflect some light, hereby creating this effect. It's as though the products are captured in a light box!