I don't like
Samuel, but I do like
Sam. I don't really like
Samson either... it reminds me of dogs because I've known several dogs named
Samson and no humans.
As far as
Sam names go, I like Samwise and Samwell. Samwise might be too hobbity, but I think Samwell is pretty useable. Unless it would get mixed up with
Maxwell...
I think it's better to have just the name you use on your birth certificate. If you liked
Samuel, then it would be good to use even if you always called him
Sam. But if you really don't care about the full name, and are just using it for the sake of using a full name, I say don't use it.