Of your three choices, I think the Lab is probably the best. I’ve never owned one, but my brother has and I’ve known quite a few - they were all great dogs. Our last two have been Samoyeds. The first, a male, was given to us fully grown and hadn’t been treated well. He was possessive and could get nasty at times, but when Matthew was born he was very protective of the baby. When Matthew was about 7 or so, we got our current Samoyed, “Snowflake” as a pup from a good show breeder. She has been an absolute sweetheart - the gentlest dog I’ve ever had.
(http://hphotos-snc3.fbcdn.net/hs075.snc3/14232_1321913126754_1198604539_31006653_2773243_n.jpg)
(http://hphotos-snc3.fbcdn.net/hs075.snc3/14232_1321910566690_1198604539_31006647_5788056_n.jpg)