It's matte.

At the moment the Xbox 360 S comes in two flavours: 250GB and 4GB, in glossy and matte finishes respectively. A new challenger is about to enter the ring though, with a matte 250GB console on the way.

There's no word on when the new bundle will be available or if Microsoft has made any changes other than taking the dust-sucking gloss finish off the machine, but when we know, you'll know.