I spreadsheet pretty rarely.

[link|http://www.plsys.co.uk/mesa.htm|Mesa] is an old NextStep app that has been updated. I've always thought it lacked polish though.

There is Mariner [link|http://www.marinersoftware.com/sitepage.php?page=14|Calc], which seems to be a carbon app that's been brought over. At $25 I don't see how you could go wrong.

Or you can run the functional but ugly open office stuff under X.