Re: What does putting my Windows installation in a VM do for me?
1) Allows multiple VMs to avoid the "this version of X won't coexist with that version of Y" sort of shit.
2) You can have email / web on Linux with (for the foreseeable future) less total risk than on Windows especially if you use apparmor on the browser, etc.. Though of course having a Linux VM on Windows could also do that.
3) Deters advanced malware from running if it detects your copy of Word, etc, is running in a VM that could be used for analysis.
4) The VM can be moved across hardware platforms during upgrades without the shitty business of re-registering it with MS.
5) In a decade's time the VM's internals (probably) look the same even though you are 3 generations of hardware down the line so you don't get a "sorry Dave, I can't let you run this OS on unknown hardware" sort of problem.
But for games then dual-boot otherwise performance will suck big time for intensive graphics.