I'm a little confused with all I've been reading in this thread about Shelties. Clearly there is a lot of variability amongst dogs individually. My sheltie was the most loving and intelligent dog I've ever known. At times, she was hyper, at times she would chill, but she was always this saintly dog that would never get snappy with anyone. I almost do not want to get a new dog because I fear I will be disapointed. She was this amazing animal. That being said, I've also met Shelties who are really annoying chihuahua-like lap dogs. Similarly, if you go to petfinder and look at all the Border Collies put up for adoption, you see many that have behavioral issues no doubt due to improper socialization.
I think when you get a dog, with the proper socialization, development, and owner input, many dogs have the potential to become these amazing animals...
So the question is, what kind of a dog are YOU prepared to raise? Good luck....