Our first free walking tour and it's made us want to do it in every city we go to now! We did the Gastown and Granville Street tour. It was a great way to orientate ourselves within the city, we found out lots of bits we wouldn't have otherwise known and saw things we wouldn't have seen. Our guide was really friendly.
There were a few things that weren't mentioned like why Vancouver was called Vancouver (which we later found out in a Seattle free tour) and he didn't really give a chance for questions but definitely worth doing.