You need to realize that TDP is theoretical maximum heat output. Idle will be less(how much less depends on what kind of settings you set in the BIOS). If you disable SpeedStep(or whatever its currently called) then your wattage will be higher than with it enabled.
My system, E3-1230V2(69W TDP) has a total system idle wattage of like 30w. I don't remember the exact number, but it was less than 35w idle. That included the CPU, 32GB of RAM, booted up and idle. No hard drives.
As for spinning down drives, I don't do it. It's bad for the drives to be cycled alot, many drives won't spin down even if you try, if you are using a jail they'll spin back up almost immediately after you force a spindown anyway, etc. So I don't have answers for spinning down because (to me) its really not worth the time and effort to try to save a few watts after all the time and effort you'll put into replacing disks prematurely, time trying to get it to work, etc. And keep in mind every time you startup a bunch of disks that starting surge is quite high. If you don't have a very beefy PSU you might burn it out prematurely too. And you definitely don't want a PSU to burn out, happen to overvolt the whole system, and fry every component in your system.
My system, E3-1230V2(69W TDP) has a total system idle wattage of like 30w. I don't remember the exact number, but it was less than 35w idle. That included the CPU, 32GB of RAM, booted up and idle. No hard drives.
As for spinning down drives, I don't do it. It's bad for the drives to be cycled alot, many drives won't spin down even if you try, if you are using a jail they'll spin back up almost immediately after you force a spindown anyway, etc. So I don't have answers for spinning down because (to me) its really not worth the time and effort to try to save a few watts after all the time and effort you'll put into replacing disks prematurely, time trying to get it to work, etc. And keep in mind every time you startup a bunch of disks that starting surge is quite high. If you don't have a very beefy PSU you might burn it out prematurely too. And you definitely don't want a PSU to burn out, happen to overvolt the whole system, and fry every component in your system.