As I recall a Microsoft NT flaw "crashed" an entire warship during a wargame... Ah, those poor souls who stray from IBM Federal Systems Division...
The threat I speak of is not to the internal military networks, which hopefully are all battened down and isolated pretty well... it is to the United States economic and industrial base. Don't try to tell me that the NSA sanctions Microsoft software because it lends itself to a more secure National information infrastructure...what it lends itself to is as a platform for remote administration trojans and denial of service attacks...