Tables for MacOSX

Currently free due to beta release, Tables is a nice spreadsheet program that can do pretty much everything you need Excel to do. The beta is a free download, so definitely worthwhile to take a look at this for sake of a Microsoft replacement program if anything else. It seems well-thought out and has the functionality that most users need from a spreadsheet program without losing too much time on re-learning the program itself.
Tables requires Mac OS X “Panther” version 10.3.9 and above.