I stick the EZ Pass to the winshield right behind the rear view mirror, I cant even see it when driving. I use one of those products that hold it on with suction cups. It is a breeze to move between cars or pull it off when you dont want it in sight.
here is one of the holders:
http://www.e-zpal.com/
and here is the one I use, very secure with 3 suction cups:
http://www.autobarn.net/ezclip.html
Enjoy!
I have no monatary stake in these products, I am simply a user.