MS were making the statements about reaching god knows how many people initially, and realisically its LIVE that is going to be doing that in the future, the gaming console is there just as the initial delivery mechanism for live.
I see Live as a giant beta test for software convergence
And you're now on beta 2.1, on the verge of 2.2 (at least in the US
). Over here it's still beta 2.
The advantage of starting such a platform on system that is locked down, is that by the time you move it to the open system, you have a significant userbase to help spread the infection. There are loads of systems on the PC that do most of the functionality of live, yet very few have similar usage figures as they all had to start from zero. How many steam friends do you have, for example?
As for convergence on the software front, some other examples:
The media centre extender is already rendering with a cut down variant of WPF,
The 360 has an implementation of the .net compact framework in the form of XNA,
Zune is sharing the Gamertag and Points system (Big one that...)
Your gamertag ties down to a Windows Live/passport account
Windows Marketplace (although currently it's more a portal)
Vista+360 demos of Shadowrun, Halo using friend invites on the PC, etc
... There are clearly more, with vista etc. Probably loads we won't know of for a while.
I wouldn't be surprised if eventually, the 360 has a full implementation of the .Net framework 3 (eg, using a generational GC, with WinFX support - probably minus windows forms, etc).
IE7 is heavily tied into WinFX on vista. I see a day when you write a WPF rendered app, communicating with WCF in C# or VB, or whatnot.. Run it through the web in IE, download it on your desktop, or run it on your 360. That in itself I see as more useful than an integrated web browser.
And really, thats what microsoft are good at, software platforms. Say what you will of the 360s hardware, at the end of the day it's the software that makes the system tick.