Unfamiliar with Apple, but I'm using Windows XP, and I've got Open Office 2.0.
Its as good as Microsoft Office Professional. That's the one I have running on my Windows computers. The problem with Mac is that since there's a smaller market for it, there's not that much software to buy. On the other hand, that makes it less attractive to people writing, worms, viruses and spyware. I don't have an anti-virus program on my Mac Mini and the only thing I turned on is the built-in firewall. Besides being nearly crash-proof, its also pretty well sealed against hackers.