Jack, What you are talking about is a double boot (except for Wubi which is a special case). But there is nothing easier than running in virtual.
With double boot you have to bring e.g. Windows 7 down and then boot Zorin which is very inconvenient. Zorin is a full operating system and has to be treated like e.g. Windows 8.
Just think of your scenario with Windows 8 - would that work ??