Upgrading from XP pro or XP home to Vista Ultimate

Remember guys, stick to the questions at hand. Don't ask me a question on top of a question. Just answer I know it's difficult to do, but restrain yourself.

If Upgrading from the retail version of XP Home or XP Pro to Vista Ultimate when it's available for the general public........

The Cost?
XP Home to Vista Ultimate?
XP Pro to Vista Ultimate?

What does the upgrade entail with both XP Home and Pro? Is it the same type of upgrade? If not, what's different?

Last question:What would you upgrade to with a clean hard drive right now? Knowing that in the future (6mths or so), you're going to upgrade to Vista Ultimate.
XP Home?
XP Pro?

To me, it wouldn't matter, because I avoid upgrade installs. Even if I purchase an upgrade copy, I always perform a clean install... the upgrade disc will allow you to do this. If you already have Windows XP, then you might as well stick with whatever version you have and purchase the upgrade of your choice when it is released.

I have yet to hear anything concrete on what the cost of the various upgrages will be... nor what qualifying products they will upgrade.

Thanks guys.
So it's XP Pro (minimum) for the upgrade.
Additional replies that add anything more........ would be appreciated

Another question:
What do "you" think it will cost to upgrade from XP Pro "retail" to Vista Ultimate?
$100.00?
$150.00?
$150.00+?