If Microsoft keeps to their Vista practice, any full package purchase of Windows 7 will be able to do an in-line upgrade as well as a complete fresh install.
The upgrade paths that will require both an in-line upgrade and an Anytime Upgrade involve moving from Vista Home Basic or Vista Home Premium to Windows 7 Professional.
To go from Vista Home Basic to Windows 7 Home Premium (in-line) would be $119.99 and then to Windows 7 Professional (Anytime Upgrade) another $89.99.
For a couple of reasons, I don't think this will be a popular choice. For one thing, computers running Vista Home Basic are probably running it because they couldn't run Aero in the other Vista versions. It's unlikely that these folks are going to want to upgrade to Windows 7 at all, much less to the Professional version. For another reason, which I didn't really mention before, some netbooks will come with the Basic version of Windows 7 (which is not to be sold at retail). Not many people will be upgrading these to Windows 7 Professional, either.
So this leaves us with what might be the more popular choice - Vista Home Premium to Windows 7 Professional (which is the equivalent of the Business version of Vista) for a computer capable of running either version. It's the same deal. Vista Home Premium to Windows 7 Home Premium (in-line) is $119.99 and the Anytime Upgrade is $89.99. This is only a $10 ding from not having Vista Business to upgrade from! (And Vista Business is still $299.95. Any way we look at it, Windows 7 is more reasonably priced than Vista was.)