I had to dig this out of the Wayback Machine, as the original tech site (http://www.tech-archive.net/Archive/Excel/microsoft.public.excel.setup/2004-06/0118.html) was down. Thought it worth reposting. Credit Gord Dibben.
From: Gord Dibben (gorddibbATshawDOTca)
Date: 06/17/04
In reply to: L Schmandt: "how to default all cells to wrap text?"
Date: Thu, 17 Jun 2004 08:15:03 -0700
Hit CRTL + A to select all cells. Format>Alignment>Wrap Text. To make
this the default for all new workbooks and sheets.... 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