Should I use the on/off power switch or turn off my power bar?

[Kammex]

After I shut down my PC, should I turn off the switch or the power bar switch? Apparently if you cut off power at the PSU, the CMOS battery will drain. Which one should I turn off?

 

[USAFRet]

Neither. Or either.
The CMOS battery won't drain down, unless you leave it off for a a loooong time.

Long = months at the earliest.