Use of "wrap text" in Excel 2002 SP-2 causes file size bloat. I have a spreadsheet with 150 rows, 30 columns. Many columns have word wrap on. With word wrap on, file saves as 3,300 KB (3.3 MB). With it turned off, saves as 190 KB (about 0.2 MB).
Doing Ctrl-End as suggested in this thread...