Ok cool, now I know there is a lot of unnecessary stuff in prebuilt desktops, if I wanted to put another HDD for storage there would be plenty of room?
Multiples or whatever you like for a storage solution. I'm not a fan of RAID at all, but IMO if you're doing a lot of VM work you will want either seperate SSDs for each VM or at least a RAID 0 setup for the speed increase.