Although there isn't an official picture of the User Interface of Halo 3, we are comfirmed that it is being updated and improving from Halo 2. This is what Frank O' Conner of Bungie has to say about it:
"Our UI has come on in leaps and bounds. For a long time the UI development was happening separately from the actual game, so missions and other options would be chosen from a debug menu. Now the UI has been rolled into the game, so you can use it like a regular game interface for most things, and see it develop along with the rest of the game.
As it stands now, the interface is designed to make it very simple to get to a "lobby" and make all necessary changes from there - so that you can customize your experience, appearance, and more importantly, really specific game types from anywhere.
Folks who've played a lot of custom games know that it is very frustrating when the "Quick Options" selection just isn't enough to get all the options you want in a game type. You won't have to worry about that from now on. And you can also change your controller setting from anywhere, at any time. That one was a given, right?
This is obviously the barest kernel of what to expect from the new UI - and there will be a lot of goodies added to it between now and then. UI gurus Dave Candland and Colm Nelson were kind enough to give me a guided tour today and I can honestly say that I finally "get it." The problem with adapting to a new UI is the problem of familiarity. You expect things to behave the way they did in Halo 2 and when they don't, it's easy to think, "Oh, that's broken," when in fact, something has technically been fixed. And the sign of a good UI is that it only takes a couple of tries to get used to it, and that everything is found in its logical place."
ONE LAST LITTLE BIT
I knew this was deffenitaly expected, but it has been comfirmed official that there will be driving in the Halo 3 campaign. It was also comfirmed by Frankie when he mentions, "...a very brief, if exciting campaign test with lots of driving in it."