Which VSTi's can use all 64G+ ?
I know of none that individually take that amount of ram. Most people have 16 or 32 gigs of ram; I have 16 gigs myself. Where you need ram is when you are using soft synths like Kontakt or Sampletank 3 where you have many patches and/or multiple soft synths. For instance I have had one Kontakt what had drums, one drum per channel and many channels of percussion instruments, 16 in all as well, another instance of Kontakt running many other instruments as well as a couple of other individual soft synths with no problems. Of course I am using a 64 bit Win 7 pro OS.
I had to have a 64 bit computer because with my old 32 bit and one instance of a 32 bit Kontakt containing one choir patch I could only do 2 measures at a time. I kept running out of memory. So I bounced to wav those two measure then went back to Kontakt. This got old very fast.
Having excellent ram intensive soft synths is why some of us want a 64 bit BiaB.