I found this article on dog intelligence extremely interesting. Psychologist Stanley Coren has defined intelligence--dog intelligence, that is--as having three parts: adaptive intelligence (the dog's ability to solve problems), instinctive intelligence (what the dog was bred to do) and obedience/working intelligence (how readily the dog learns from its owner.) Based on estimates of how quickly a specific breed of dogs learns and how often it obeys, Coren has come up with a ranking of the intelligence of various dog breeds.
Border collies top the list. Poodles are second.
Two of these domains are comparable to how human intelligence is defined--speed of learning and problem solving--but a definition of human intelligence would tend not to include a dimension of "instinctive intelligence."
For something very amusing, read Hyperbole-and-a-half's account of trying to measure her dog's intelligence.
"A lingering fear of mine was confirmed last night: My dog might be slightly retarded."
"I've wondered about her intelligence ever since I adopted her and subsequently discovered that she was unable to figure out how stairs worked."