I am an owner of ZuneHD and love it, although I wish it had Flash so I can view youtube, etc. Here is the main problem I see why Microsoft will not release flash support for ZHD even though it is very simple thing to add. We all need to blame one thing, Silverlight. If Silverlight wasn't arround, chances are we would get Flash but since Silverlight is in competition to Adobe's Flash, it would be very embarassing/ not a smart business move on Microsoft's behalf to implement Flash in Zune HD. Again I HOPE I AM WRONG AND WE GET FLASH.
My Understanding of Silverlight is not so thorough to know it's technicalities. What would be really cool if Silverlight can play .flv's, .swf (flash formats). Just like OpenOffice can open MSWORD files, etc, if Silverlight can do that, it would be incredible. So, on that note there is a chance we might get flash playing ability on Zune HD, but definitely NOT Adobe Flash, maybe from Silverlight (if it is ever released on the device). Once again, I hope my prediction is wrong and we all have flash