If you're always expanding the width of your cells in Excel, perhaps the default width isn't working for you. Here's a quick fix that works in Excel 2007 and Excel 2010.
On the Home tab, click the Format button in the Cells section and then select Default Width:
Now enter a number that represents the number of characters you want to fit in the cell (the standard default is not quite eight and a half characters, which includes a little padding):
Pick a number that you think will work for you most of the time. It's easy enough to change it again later.