Ugly ones. Steve Jobs has to wear blinkers while touring the aisles.

Apple mostly uses Sun machines. I was surprised to learn this, but they tend towards a conservative, heavyweight server infrastructure.

Not sure how accurate this picture is, but I see xserve's and sun servers there: http://www.cultofmac.com/interview-apples-gigantic-new-data-...

Does anybody know the answer to this? I too am quite curious.