Remote Desktop - RDP/VNC/X forwarding
Overview
Another option is the use of a remote desktop protocol. This is a fairly brute force option as you need a machine running your target operating system.
Performance
The performance of this option may very greatly. CPU related performance should be equal to that of running the application natively (because you are running it natively), but the interface will have a little lag depending on the connection between the machines.
There are a variety of solutions, there are some reports of windows rendering opengl applications locally then pushing the image over the network using RDP correctly, though it is slow, and most likely unacceptable for most applications.
Photoshop runs over a gigabit lan well enough to be usable for usual texture sizes.
If you are connecting to a linux machine over VNC you can look at using VirtualGL and TurboVNC to connect and this will give you hardware accelerated opengl over the network. Though even using ssh with X forwarding on a local machine with a 3d graphics card should forward the required calls to use your local graphics card for acceleration. The benefit of this is that it enables you to use linux software which does not have a floating license from multiple machines. Because the software is executing on the host and only the display is being forwarded to another machine.
Ease of Use
RDP and VNC require launching of a separate application which provides a window, which may be made full screen, of another operating system. So will be a somewhat similar experience to using a virtual machine.
If you go the X Forwarding route then if you setup ssh key authentication you'll be able to provide an entry in the menu to launch an application. Remember this option isn't available for windows, but may work with OSX (untested - please let me know if you do) as it's unix based.
You will also lose any pressure sensitivity and angular detection on wacoms through these options.
Ease of Configuration
All these options require installing and configuring the server you will be connected to. Depending on your choice of technology it may come standard, RDP is a standard part of windows and most linux clients have a VNC application in their package manager. KDE 4 comes with a nice remote desktop client that supports both RDP and VNC. Almost all linux distros come with ssh installed by default. So your main task will be enabling X Forwarding and, optionally, setting up key based authentication.
Flexibility
These options allow you to run software from virtually any operating system and have the advantage of emulating floating licenses for applications which do not support it.
Cost
There are free software options for all of these technologies on linux, and windows comes with RDP by default. There are vnc servers available for OS X and it comes with X11 and ssh by default. Though you will need to buy hardware (and possibly an operating system) to use this and so it could be the most costly option depending on your requirements. Though if your software doesn't have floating licenses and you need only a minimal number of copies, but need it to be able to switch between machines, then you may find that this option can save you money.