A user suggested we default our Excel 2010 workstations to open 1 sheet when opening a new document instead of 3 which is default.

This is accomplished via this setting in Excel 2010

And via this registry key

[HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Excel\Options]

“DefSheets”=dword:00000001

Changing the last number as appropriate.

So Group Policy to enable this company wide is as simple as

As with any GPO or registry changes, you should apply this to a test group first before rolling out across the entire domain.

That all being said and done, There is not a good reason to do this as the size difference is minimal. Although maybe you will find this useful.