Border Collies.
And I love Rottweilers as a second.
I like a LOT of breeds, though, and I am a definite dog lover in general.
Some other breeds I like (in no order): GSD, ACD, Fila Brasileiro, Greyhound, Belgian Tervueren and Malinois, Great Dane, Pharoah Hound, Ibizan Hound, Podengo Portugueso Pequeno, Saluki, Siberian Husky, Akita, Shuba Inu, Lundehund, Alaskan Klee Kai, Redbone Coonhound, Doberman, Golden Retriever, Labrador Retriever, NSDTR, Kooikerhondje, Weimeraner, Kelpie, Australian Shepherd, Greater Swiss Mountain Dog, Beauceron, Dutch Shepherd, Chihuahua.