His reaction would be severe if you tried to pitch a Zune at him. I don't think he'd feel threatened by seeing an employee using one, the way Ballmer clearly is when he catches somebody with an iPod.
"Hey, I know neither of these guys, have never met either of them, and wasn't actually at the event where the infamous 'Ballmer mocks iPhone guy' incident happened, but clearly Ballmer is threatened and Jobs isn't!"
Plenty of Microsoft employees have iPhones. Microsoft makes several iPhone apps. I know several people whose work laptop is a Mac (usually running Windows). And--as you might expect at any good technology company--Microsoft employees are some of the first to try out any new software or gadget.
Ballmer feeling 'threatened' by the fact that an employee is using a non-Microsoft product? Don't be silly.
