My system consists of a Quad Core extreme, and 4 Hard drives (1 250gig, and 3 1tb, two of the 1tb drives are in a mirror array as D drive) running Win7 x64 Ultimate.  I do NOT install anything to my C: that is not OS related.  C is ONLY for my OS.  Period.  No exceptions.  I have relocated my users folder to D: as well.

On D: I have a "Programs" folder.  Under that , "Utilities", "Graphics", "Games", "Programming", etc.  This is where ALL progams install.

That said, my poser 2010 is in D:ProgramsGraphicsPoser2010 and Poser7 is in D:ProgramsGraphicsPoser7.

My D also holds a "Docs" folder root.

My runtimes are in D:DocsPoserPoser7Runtimes and D:DocsPoserPoser2010Runtimes.  My scene files get saved to D:DocsPoserDocsPoser2010 for example.

I run a domain controller so I have an active directory system.

My D:Docs folder is shared to authenticated users only.

I also have two NASs with 2 1tb drives as a mirrors in each one.  These are where I keep always available files and my backups including poser scenes.  I swap out 1 drive in each one each month as an offline/unplugged backup and let the NASs rebuild the mirrors with recycled prior month's swap drives.

Hope this helps.