Hmm... not sure what you mean by a digital HT... Most useable inputs of any HT are actually analog inputs. And even analog HT systems have digital optical or coaxial inputs. As for devices, even my 5 year old LG had a digital coax out. So, digital inputs and outputs abound, even in the analog world. What you need for CEC is HDMI, so even if your analog receiver has one HDMI port (which is also digital) - and many do - CEC would work. I don't even have an HT, and I'm in favor of CEC, simply because my DVD player and TV would support it. I don't want my kid or wife fiddling with switches and plugs, so I have ONE switch which controls the power for the whole lot. Devices in standby consume very little power, and they are only on standby while my TV is on (otherwise the whole thing would be switched off from the 'mains'). Of course, no system in the world can power up a device which is 'fully' switched off.
A universal remote is certainly handy here: specially the ones where you can record macros - so one button press can actually send out a series of commands to multiple devices - but remember, they have to be powered on too (but may be on standby).
CEC is a standard that works over HDMI - and it needs a fully-capable HDMI cable. That doesn't refer to the quality or build, but the wiring. Some very cheap manufacturers get away by only including the internal wiring needed for digital AV, but nothing more. However, as I mentioned, the cable I got with my Samsung worked fine, as did some other - cheaper - cables I tried.
Finally, if I may say so, it's a matter of convenience for me, and to a certain extent I feel safer that my family doesn't have to dabble with power cables/switches etc. And all this comes at NO additional cost to me (almost all LCD/Plasma TVs have HDMI and some form of CEC, as do most DVD players with HDMI. You will anyway be using an HDMI cable to connect the two, it's just a question of using it fully.
Well, unfortunately my Phlips 5.1 channel home theatre is analog and it doesnt have a digital input facility. So for me, CEC would be of no use. I am thinking of getting a universal remote. Does a universal remote do everything than a CEC stuff can do?