I personally hate new tabs. I also hate that xls and word closes all open documents by clicking the red x, sometimes WITHOUT saving or asking about saving the other open docs. I don't see the reason in this, and I wasn't able to find an option to stop this incredible behaviour.
Easy. Upgrade to a real operating system. Try Linux, *BSD, etc.. There are lots of options out there.
If you are determined to stick with BillWare, you might give OpenOffice a try as a replacement for Word and Excell.