I never use virtual machine before.

I plan to partition my hard drive (250GB) on a Thinkpad T400 laptop (8GB main memory, and install Ubuntu 14.04 as my main and host OS. 

In the future, when I have to use some Windows software (such as Adobe Acrobat, MS Office, SAS), I will install a virtualization software program such as Virtualbox, KVM or VMWare Player, and then install and run Windows 7, 8.1 or 10 as a guest OS. 

Since I now plan to partition my disk, I want to leave enough space for virtual machine and guest OS (even though I might not need them now), and have some questions:

* In what partitions will the virtualization software program, and the guest OS be installed respectively?
* If not considering what software applications which I will install and run under the guest Windows, how much space should I give for the guest OS and the virtualization software
* if considering the software applications which I will install and run under the guest Windows, are the sizes taken by them similar to the sizes when they are installed under a Windows installed directly on a computer? E.g. will MS Office take up the same size when it is installed on a guest Windows as it is directly on a host Windows?

Thanks.