There can never be a replacement for the crap that is M$office. Even a brainless moron cant write such crap.
There are at least two SUPERIOR alternatives Openoffice and Koffice.
I use ubuntu 8.04 as my desktop at home but i need excel at my workplace on my laptop. I have tried using OO (not tried K Office) but the spreadsheet tool just does not seem to work well enough especially after i have used excel, OO seems so dated and clunky in contrast. I must admit i have not tried the latest version though.
There is no real Autocad replacement, even if there are like BRL-CAD, Varicad etc we do not get candidates for them. We tried Virtualbox. did not work very well, especially cumbersome when it came to sharing files on a network using Samba.
I know there are other linux options for virtualization available like parallels and vmware but we are not in a position to experiment as of now especially after virtualbox.
We use an MS Access based system (third party )for excise, i haven't come across any package in linux as a replacement though am sure one could be built.
For how many users?
about 5 in one unit ..
SG