CMYK is not colour
The question asked was how does everyone prints black. And I am sure most out here already know this, but for the benefit of those that do not... here goes.
Since there are so many different combinations of CMYK that have posted to create black it is obvious that CMYK is not colour - colour should be defined by a unique number, and that's the LAB value.
So when using a good profile to print , that profile will take all the lab values and map it to the correct amounts of cmyk inks to be used.
So even if u use one of the combinations of CMYK values suggested , it will still not get you better results. A GOOD profile and regular LINEARIZATION on your equipment is the BEST solution for predictable and consistant colour.
Lastly - colour spaces, try this simple exercise in core/Photoshop etc. Punch in any cmyk value as suggested, defining your colour work space to say uswebcoated, then get the LAB value of this 'black. Then change the work space to say - isocoated, and then get the lab value of this 'black - see the difference.... so even when u send artwork out with 100% black or combinations of CMYK - not respecting colour spaces will give you different results.