I suggest you get a large enough SSD that you can include everything except your User data.

Then copy your active User folders to the data HD, link them to the related Library - Include a Folder - Windows 7 Forums. This prevents issues caused by moving the shell User folders.

If you run out of SSD space then I'd uninstall lesser used programs and reinstall them to the data HD. But you will suffer a speed loss because SSD speeds benefit programs as well as the OS which is why they should not be installed to a slower HDD.