The concept is termed ETTR.
While it might not make me seem like a pro (hey, I am not!): I didn't know about that, thanks again dr. neuro!
The only thing left for me to wonder when shooting at low light is if it's better to have a properly exposed histogram at higher iso or a histogram that leans to the left at lower iso. Using lr4 and its smart shadow recovery, I'm tending towards the latter with my aps-c sensor, because higher iso than 800 really ruins the picture while 1ev underexposure does not.
That is a question that there may never be a definitive answer for.
In my experience it depends on the camera. Some cameras whose high ISO modes are just "software enhanced" are better used at lower ISOs with slight underexposure, and then pushed on the comupter with software that is better designed and can increase the brightness without resulting in as much nosie as the in-camera "software-enhanced" ISO boosting.
For other cameras that really do have the ability to increase their light sensitivity, it is absolutely better to increase the ISO to get more bits of detail in the file, and then try to decrease noise later. Underexposing reduces the actual amount of data that is captured in the scene. So in an ideal world, you would get the proper exposure by increasing the ISO, and then reduce the nosie in post-processing, and your image would have higher quality than shooting underexposed and then boosting the ISO with software.
It all depends on whether the ISO level that you are shooting at is provided by the intrinsic analog/physics capabilities of the image sensor physics (in which case you should shoot at high ISO and reduce noise afterwards), or by the camera's image processing (in which case you should shoot at lower ISO and increase brightness afterwards).
Boosting ISO with software always reduces the amount of usable data in the image (which is why the Nikon D4 only has 6-8 bits of DR at ISO 200,000, because it is software boosted). So that is what you always want to avoid.