The mac version of open office is NEOOFFICE. It does everything I need it to do for interfacing with MS office docs and the cost was $0. 😀
An aside, if you use a virutal machine to run PC apps, you'll still need to invest in a copy of the PC OS, be it Win XP or Vista. The total cost of virtalization is the virtualization software + the OS software + the actual app you need to run.
On the plus side, VMWare Fusion 2 is currently $25 after rebate at Amazon - huzzah!