I had a chance to use Apple’s Numbers spreadsheet program for significant work today. It’s really quite good for home users and small businesses. I like the separation of individual tables in the workspace: it more closely matches the way most people actually use spreadsheet programs.
If you need legal Mac office software, don’t bother with NeoOffice (Mac-native OpenOffice port). It’s not worth free.
The $70 for iWork is a much better deal than Microsoft Office for Mac ($131 for noncommercial home or student use, $355 otherwise) if you don’t need to frequently interact with Microsoft’s file formats.