I'm just about to assemble a new PC with Win 7 64bit.
I've just done that
see:
http://ddisoftware.com/tech/computer-hardware/qu-is-now-flying/Should I put Qimage Ult on one HDD complete with all its associated thumbs and RAW cache or should/could I put some QU items on my second HDD?
You could put the application/program data on a separated HD but I would think for maximum efficiency & speed, the same HD should be used.
My new PC has 2 1TB drives and I'm using C-drive for all Programs, Program data and a large number of images and other data. Not all image are there, the archive of older images is on an external HD and on DVD's. The second 1TB drive is/will be used for multiple backups.
With having 2 large hard drives and backing up to one of them, for me, I don't see any point in separating data from programs and certainly not separating program data from the program.
Sorry, I can't comment on SDD.
Terry