Dave

Open a new workbook.  Customize as you wish.  File>Save As Type:  scroll down
to Excel Template(*.XLT) and select.  Name your workbook "BOOK"(no quotes).
Excel will add the .XLT to save as BOOK.XLT.

Store this workbook in the XLSTART folder usually located at........

C:\Documents and Settings\username\Application Data\Microsoft\Excel\XLSTART

This will be the default workbook for File>New>Workbook.

You can also open a new workbook and delete all but one sheet.  Customize as
you wish then save this as SHEET.XLT in XLSTART folder also.  It now becomes
the default Insert>Sheet.

More can be found on this in Help under "templates"(no quotes).

Gord Dibben Excel MVP