I generally filter at lights, if it will give me an advantage. The exception is large trucks (and some SUV's). Most of the cycling fatalities in TO involve a cyclist being dragged under the rear wheels of a truck. I try not to pass them, or let them pass me (when I feel there's not enough room for both of us in the lane).
I'll filter past a line of cars waiting at a light, with parked cars in the right lane - but I'll go slowly so that I can stop if someone decides to give me the door prize.
I won't filter to the right of a cager signalling a right turn - I'll go to the left. We call people who pass right turning cars "statistics" here