1st run (not 100%): about 55 h
2nd run (not 100%): almost 30 h
3rd run (100%): about 33 h (getting the Hylian Shield took me forever...)
4th: right after entering the Lanayru Mining Facility around 7 h
Hmm... didn't really take time, and I got it in the middle of the exam month, so my first playthrough was a lot broken up, but I guess it took 60-70 hours or so.