I'd really like something that does tabs like Micro$oft Excel.
As far as I know none of the Amiga spreadsheets have tabbed sheets. Other than that the recommendations so far should all be fine and the ones on Aminet are the best place to start.
I think Terminills may have got the rights to Final Calc along with Final Writer so that may see further development. Tim?
There does seem to be some ongoing development of Ignition with a newer version existing for OS4, according to the Sourceforge page it should still build on 3.9. There is a mailing list so you could join that to discuss the likelihood of tabbed sheets being added to the list of features.