Mike - nice to see you posting such detailed responses, particularly letting us know about bug and releases.
When I edit channels, specifically when I'm changing channel numbers sometimes when I hit "previous" it will take me to the channel that is -1 of the NEW channel number, rather than the -1 channel of the original channel number. It makes it a right pain to run through all the channels, because you don't now where you've got to.
It seems to be different on different "visits" to edit channels - sometimes when you go in it does do it, sometimes hitting previous takes you -1 of the original channel.
Not being able to play the new format on MCE2005 it a nightmare as well - I have two other mediacenters that aren't able to run Vista.
Also, I've noticed that sometimes when I'm scrolling through the guide, the preview changes in the bakground.