Last change to edit my build! Need opinion on VMs!

EDIT: title was supposed to be last CHANCE to edit my build >.< (because I will buy it on Sunday 17)

I am a programmer, that like programming games, and like playing games too.

I need a 3 OS build, Linux (my "main OS"), Win7 (most broad game compatibility for now, since I also play some old games that don't run properly on Win8+), OSX (my main source of money is doing OSX coding, I need this as a backup, in case my MacMini die or something).

I thought of doing something that maybe I can boot a VM from, using Linux, and booting Windows and OSX with VMs, but I never did that before, so I dunno how many GPUs I need and whatnot.

Still, this is my build idea, should I change it somehow to better suit my needs? (by the way: yes, I put 3 HDDs there instead of an SSD... I need the space, and I am not bothered by the loading times that SSD reduce, I plan in buying SSDs later then they improve and get cheaper, or I get richer...)

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