I think it can completely vary and is not always necessarily linked to breed. That being said, we've got a long-haired Tortoiseshell with some (we think) Norwegian forest traits (She's a big cat, big crest of fur and big paws).Just found this thread and it makes me want to get a cat a lot. Any recommendations for the most 'dog like'? I've always had a soft spot for a cat this gives affection.
She is massively affectionate - constantly wants attention, or wants to give you attention. Admittedly, this can be a bit much at times (especially when she insists on sleeping between me and the wife, but I wouldn't change her for the world.
Apparently Maine Coons and Rag-dolls are supposed to be very affectionate, but this may not always be the case!