With the Sphygmic Software spreadsheet you get all the functions you need in less than 4MB.
Build formulae using the 125 built-in functions, including text handling, statistical, date/time, and financial functions. Worksheets can span 256 columns and 16,384 rows, enough for almost any task, and you can work with multiple sheets at once. You can import industry standard CSV files and read and write Excel 4.0 files.
The built-in charting module is both simple to use and highly configurable. Select a chart range and you get an instant chart. If you need a slim, fast spreadsheet that won't bury you in irrelevant features.