Dejan,
You asked me to cut one of the cables in half and re-measure, just to "prove" to everybody that these meaurements are related to cable length.
Instead, I found another "commercial" PC power cable which is only 1.7m long.
Its measurements were:
L - 0.0023 mH
R - 0.245 ohm
C - 0.1665 nF.
These should be compared to the original cable's measurements:
L - 0.0031 mH
R - 0.4 ohm
C - 0.2735 nF.
The original cable is 2.8m long and the shorter cable is approximately 1.7/2.8 times the original values!!
Regards,
Andy
Thank you again, Andy, a job well done indeed.
I think your measurements show quite clearle that shorter is better, as opposed to certain other aspects of life.

Truth be told, my power cables are all below 1 m length - no need for them to be any longer, since they are all plugged into the DeZorel Audio Reference Senior line filter. This in turn has its standard cable 1.8 m long, close enough to what you used in the second bout. 3x2.5 mm cross section, so I expect it's rather good, since it's been rolled in oiled paper first, and then insulated by natural rubber. I'll see if I can measure its characteristics, just for the record.
Cheers,
DVV