"Pendant" is more frequently used and "durant" is a bit more formal. Otherwise, they're pretty much interchangeable and the difference between the two is similar to the difference between while ("pendant") and during ("durant"). Not a native speaker, got that from here: http://forum.wordreference.com/showthread.php?t=371805, so feel free to correct me.
Yes, I wrote "throughout the night" and it didn't like that. Does "durant" have a flavor of being momentary ("in [durant] the night, the vase crashed on the floor")? Or does it also (or instead!) have an implication of being ongoing ("in [durant] the night, the bird sleeps")?
Just an advice for the english speakers who have trouble with pendant and durant: for the most of the time there isn't a most correct word or a most used. They are synonymous, just that. In latin languages synonymous are very more frequent than in the english language. And synonymous are used, without rules and without "what is most used", it really depends which word the person fells like saying at the time.
I know this fells annoying, but this is what makes latin languages more lively.
Surely you jest. Though not my first language, I fell in LOVE with this most splendid amalgam of European languages very early in my life........my sadness has been great (interesting synonym, also consider "terrible" as a synonym for "very") to see how it has devolved not only en Amerique but in the country of it's origin. It seems somewhat dangerous there to speak it today as it was in Somewhat Recent times with the most appropriate dialect and vocabulary to suit the language......it is "thought ill of".......a rebellion against all kinds of things.....please don't throw the cat out with the cat litter....it REALlY is GRAND!!!