Well the ones that are really smart are good to actually train, but they are the ones that also need a lot of exercise and attention because they are smart but also high energy. Huskies, australian shepards, golden retrievers, pitbulls and german shepards. Probably german shepards and golden retrievers because those aren't as high energy or "red zone" as the other dogs.
Standard poodles are very easy to train. They are extremely intelligent. People mistake them for fluffy,dumb show dogs because of their hair cuts. The truth is that it was originally cut that way because they are hunting dogs like a retriever. The hair poofs are to keep their joints and internal organs warm in cold water. The tail is to be able to see them in the water. They are great family dogs and highly trainable to do almost any trick you can think of. They are used in circus acts because of this trait. The one draw back is that unless you can cut their hair, they are very expensive to maintain. They have hair not fur, that continues to grow if not trimmed and can mat quite easily if not brushed often. They do not shed and are great for those with allergies. They are one of the funnest dog breeds to own and can be very entertaining and comical. They adore their humans and can become very attached to one person in the family. The smaller poodles also have these traits but the toy and the tea cup have more health issues than the standard or miniature. Diabetes and blindness are two.