What's the typical upgrade path with MS?

Hi,

Am excited to be getting a new "beast" of a computer (maybe even by this Friday). I will be installing Win7 x64 (still in its sealed box) so that the 6 GBs of RAM can be utilized.

Next, in goes Office [12] Pro 2007 (also still sealed). I am planning to upgrade to native x64 Office [14] Pro 2010 when it's released.

I am also considering running Office [14] Pro's ~beta~ now (well, maybe Friday) which I understand is available.

Here are my questions:

Can anyone venture a guess (from past experience) how much the upgrade from [12] to [14] might be?

Is the final release usually available BEFORE the beta becomes disabled on October 31st? (I'd rather go ahead with the upgrade than be forced to uninstall [14] and reinstall [12])

TIA

--drcarl