From what I've read....not a lot.
Bottom line....
If you have to ask this question, then there is nothing in 2003
that is worth the upgrade.
For a little more on this, read JWalks comments on it. http://j-walk.com/ss/excel/xl2003.htm
He's written a lot of great books on Excel.
He was a beta tester for 2003.
He had it, tested it and from what he writes, he's back to 2002.
You can click on the various products to see what's new.
--
Regards
Norman Harker MVP (Excel)
Sydney, Australia
(e-mail address removed)
Excel and Word Function Lists (Classifications, Syntax and Arguments)
available free to good homes.