This comparison chart appears to be very detailed.  I have no idea if the preloaded Virus line item is valid. Click the picture for full details.  One thing I did notice is missing, and it's a biggy.  The chart currently doesn't have the video out capabilities.  The new Zune 80 has some impressive transcoding and output display capabilities.  See http://zuneinsider.com/archive/2007/10/05/in-which-i-attempt-to-answer-some-zune-questions.aspx for the details on that.