I am a big Mac user, right now I am typing this post on my iMac. Also in my office, you will find a MacBook and a Mac Mini. At home, I have a Mac Mini too. But there are times when I need to run other operating systems for testing like Windows and a flavor of Unix. Since all of my Macs are Intel-based, I am able to take advantage of the virtualization software that is available. I have tried Parallels and VMware Fusion. Under both of those products, I installed a licensed copy of Windows XP and Ubuntu. In the end, I really liked VMWare for its features and performance. Heck, I even went out and purchased a copy for home. Now the landscape has changed a bit. A while back, Sun released VirtualBox as Open Source, which is another VMWare-like environment. From the VirtualBox site:
VirtualBox is a general-purpose full virtualizer for x86 hardware. Targeted at server, desktop and embedded use, it is now the only professional-quality virtualization solution that is also Open Source Software.
So I kicked the tires on it, and the results have been very good. Again my main use is to fire up an OS and maybe do some testing and that's about it. In the hard times we are in financially as a country, you really cannot beat the cost ($0.00).
I'll second that! I have a CD copy of it in my office I picked up from MacWorld, in case anyone wants to install it without waiting for the download. Now with the 3D acceleration, it really performs well, IMO.