I think its inevitable but what was integration is currently missing? The Zune HD already has integration with the video service, and as for games, the problem their is that the games on the 360 are built to run on i believe a dual core system. I have the Zune HD and i think the 360 integration so far is fantastic, especially the cards, and video. Now I personally think Windows 7 Mobile will be a combination of the Zune OS with Windows 6.5, and if thats the case its going to be one hard OS to top, although I am not ditching android for it. Now as for apps, I definitely think we will see some more hit the market once the mobile version gets announced and the SDK goes public, its inevitable really. Now the killer point would be if they are cross compatible with the 360 and windows computers. That is something not even the iphone can do.
Integration with the xbox live friends list would be awesome, to allow messaging from a phone to xbox.
So XBOX Live integration is included and you can edit your 3d avatar (which it will be 3d) on the phone as well. Just a tidbit for the people that didn't watch all the demo videos. More is supposed to come out at the Mix conference next month
It's already integrated into WP7S and it's integrated in a big way. From the looks of it, when people nudge you on 360 to play a game, you will get that nudge on your phone. All your profile stats and achievements from your Xbox Live profile are there on your WP7S phone and any Xbox Live games you play on your phone will add to your achievements and what not in Xbox Live.
This is a great idea, in my opinion. I think the key here is to have depth. I want to be able to buy a really good game for my phone (as good as a mobile game could be), play it, and have that reflected on my XBL Account. Additionally, I'd expect online multiplayer for games like PGR or whatever.
I think Microsoft has an all new gaming platform on their hands. If they can make it cross-compatible with the Xbox 360 in many ways (particularly the XBLA or even Indie Games), everyone will have their Xbox Portable, which will double as a phone.