50 minutes if the traffic lights are cooperative, the train comes right as I get dropped off, the train is super awesome and it's not in peak hour, and there's no slow walkers blocking me from Redfern to uni.
However, that has never happened all in one go, so an hour.
Longest commute I know of is someone who lives in Kincumber on Central Coast--half an hour drive to Gosford station, 1.5 hour train ride to Redfern, 15 minute walk to uni. That's pretty bad.