Canada was the best. I got a ride from a native american who smuggled me aboard the ferry he worked on, so I could cross to Prince Edwards Island for free. I got a ride from an older couple and their grandson in a camper, who invited me to stay with them at a campsite (and gave me my first taste of Moosehead lager). And in Newfoundland, apart from plenty of good car rides, interesting conversations, (and being invited for Moose meat dinner, and even overnight stays) I got a 'ride' from one coastal village to the next, from a couple on a tiny boat, that were motoring around Newfoundland.
In France and the Netherlands I did some hitch-hiking as well, both for practical reasons (when there was no bus), and for fun. Was a bit harder there, but on overall it was great. Australia was ok too, though it could be a while before one got a ride...
What I especially liked about it is the enormous diversity of people that one meets, and the life-stories they can tell. From a factory worker on his way home from the night-shift, metal-heads in a minivan heading for a French rock concert, and people racing across states to visit an ill relative, to doctors on holiday in their BMW, and land-lords making their round in a cabrio sports-car.
Thumbs up to hitch-hiking!