Microsoft's Windows Terminal Services servers always required a Windows CAL and a Windows TS CAL. These were used on a per-user or per-device basis. In the past the matching Desktop OS always come with a built-in TSCAL. Thus Windows 2000 Professional had a built-in Server CAL and TSCAL for Windows 2000 Server. Windows XP came with a built-in Server CAL and TSCAL for Windows Server 2003. I would have expected that the desktop counterparts for Windows Server 2008 (Windows Vista) and Windows Server 2008 R2 (Windows 7) would have a built-in server CAL and TSCAL/RDS CAL (as the case may be).
I am yet to see any Microsoft pronouncement on this. Does anyone know if Windows server RDS (2008 R2 and future Server OSes) will never have a desktop OS that will have a built-in RDS CAL?