My iMac, 2 GHz Core 2 Duo, 3 GB 667 MHz DDR2 SDRAM, Snow Leopard, continues to give me slow response (spinning beachball) when I use any of the Office X applications. I added 2GB of Ram as suggested but that did not solve the problem, although it did speed up everything else. My activity monitor spikes to about 90% when I open, save or close any of the Office applications.
Thanks for any help.

Office X is pretty old and using the Rosetta PPC to Intel translation to run.

Office 2008, with all patches, is faster (native instead of PPC app and some optimizations) but still isn't great. The iWork programs are generally a lot faster, but are not 100% compatible (they will not support all features of Office documents). But depending on what you are doing, they are generally good enough.

Note that Office 2008 does not support VBA scripts, so if you have any scripting in your Office documents, the highest you can go is Office 2004.

Another alternative is OpenOffice, a free alternative to MS Office and iWork. It is also not 100% compatible, but again may be fine for what you need to do.

Another alternative is NeoOffice.