Vista x86 and x64 do not come on the same disc. The combined size is
greater than fits on a single dvd. The retail Ultimate editions are
confirmed to have both dvd's in the retail box. The other editions may come
the same way.

You only get one license even if both dvd's are in the box so, no you cannot
have both versions installed at the same time using the one product key.
You may switch, but only by uninstalling the first one and then installing
the other.

There is an article today at http://blogs.zdnet.com/microsoft/?p=201 about a
plan that would enable you to do what you want provided you buy Vista
Ultimate at retail.

"Ravynne" <Ravynne@discussions.microsoft.com> wrote in message
news:036AD497-034E-4FC7-A347-764C3F674FD9@microsoft.com...
>I have been reading up alot on vista, and so far I havent seen any answers
>to
> the two question I really have..
> When Vista comes out in stores to buy, does the vista come with both 32
> bit
> AND 64bit in 1 disc so that you can chose which one to install?
> And is it possible to have a 32bit Vista on 1 harddrive, 64bit on another
> harddrive using just the 1 Vista with the 2 formats that it comes with?
>
> I have 2 harddrives, and since I know some of my games and softwares can
> not
> work in 64bit yet it does work in 32bit, I want to have the opportunity to
> use the 2 formats so that I can chose which one I want to use at the time
> Im
> on my computer.
>
> Thanks