These are the settings on my monitor:
Color temp: User
Of course the color calibration is different for each monitor. This is how I calibrated my monitor:
1. Gamma: go to http://www.lagom.nl/lcd-test/gamma_calibration.php
, your gamma should be around the 2.2 mark for each color. In my case gamma 1.9 in the osd was the most correct.
2. Colors: Color temperature "Normal" was almost perfect on my monitor. So I set the color temp to "normal" and checked what the values for Red, Green and Blue were in this mode. Then I switched to "User", entered these values and tweaked them a little bit from here (in my case I added 3 blue).
3. Ergonomics: make sure that the top of the screen is around the height of your eyes and tilt the monitor slightly upwards to reduce background bleed and reflections. This helps a lot for the blacks of the monitor.
4. Software: In game or Nvidia control panel > "Adjust desktop color settings": make sure that these are the default values ("other applications control color settings", "Digital vibrance" + 50% and "Hue" +0%)
5. Windows: You can still fine tune your calibration settings using Windows "Color management" or the Nvidia control panel