I am a consultant working with Linux/MS/Apple systems. To be able to do this, I need to be able to work with all OS's at all times. Now, I have a way in which to do this using Linux as my base OS.
You all probably have heard of these, but just in case you haven't, here is how my own system is configured.
Mandrake Linux 9.2 as the base OS. This gives me a rock solid platform and great security. Also gives me amazing networking tools.
NeTraverse www.netraverse.com Win4Lin is installed on this system to allow me access to Windows ME. This lets me have a Windows environment for demonstrating and testing applications for clients.
PearPC http://pearpc.sourceforge.net/about.html. This allows me to run Apple's OSX on my laptop for demonstration and testing purposes. This emulator is not perfect, but it is better than carrying around a PPC laptop as well.
Now I have just started playing with the PearPC emulator, but I am impressed so far. If anyone has had any experience with it, please let me know your thoughts.