Did you use a reflect map or UVW images? .. Or both? ^^
i looks like it had a base marble texture, a reflect map and some raytracing with a falloff map.
FYI: HDRI stands for high dynamic range image and is basicaly a picture of a highly reflective chrome ball converted to a format that will reflect with alot more depth than a regular enviroment map. The biggest difference is the fact that it stores the colour value information in floating points instead of 255/255/255 types. This gives it the ability to seem to excede pure white light and change the light levels in the image in the same way as a camera.
I also used the hdri in the skylight slot, this made the light seem to come from the little lights in the image you see reflected.