What you describe is exactly what VMware View is made for. With VMware View you would create only one (or only a few) templates on which you install and maintain the common applications and - depending on your needs - use ThinApp to virtualize applications, which are only needed by a few people. These applications can then be linked to the virtual desktops - deployed from the templates - and appear to the end user as if they were installed natively. VMware View also offers the ability to connect to the virtual deskops from the Internet through a security server with a bandwidth optimized protocol (PCoIP). What the end user will get - no matter if he uses a thin or fat client - is a Windows desktop with all the applications he needs.
André