One mac many OSes
With a single mac computer there is no need to have multiple machines in order to boot windows, mac and linux.
Good place to start: http://lifehacker.com/5531037/how-to-tri…p-required
This solution is great if native OS is needed in order to use hardware to the full potential or if the software virtualization solution is not sufficient for other reasons.
For the software virtualization solution my choise would be:
1. open source VirtualBox
or paid solution :
2. Parallels