What’s the best type of dog to own?

I love all dogs but I don’t own one myself. I ‘borrow’ other people’s when they’re away (basically unpaid dog-sitting but I’m OK with that!) and I love all of them.

If I got a dog of my own I would adopt one in a dog’s home, I wouldn’t buy puppy (although I love them!). And I would be very happy with a mixed breed – I would just want one that was very loving and, ideally, intelligent. But if I had to choose a breed it would either be one of the terriers or a spaniel.

What breed do you think makes the best pet?