Mark my words, they are going to change and delay just like Vista. What was Vista called in its early days? Longhorn? The name Vista wasn't around till mid 2006 I think, so whatever rumours you know now, they are going to be very different when the next OS comes out.
I don't think they were saying Longhorn was going to be the name. They said codename Longhorn. That's what they're saying about Vienna. Vienna is only the codename.
They're starting almost completely from scratch apparently. If that's true, it'll make it a completely different release then any other since at least Windows 2000. Plus, if they dump most of the code that makes up the 50 million lines for Vista, we could end up with something great. I think it's too soon to be saying it's going to be the same as Vista or any other release.
But it's probably too soon to be so optimistic like me, and it IS Microsoft...
I'm just trying to look at the best possible instance.