My mom, even though she is more like a friend than a mother. My husband isn't at all close to his mother, he doesn't care for her much even though he will talk to her. I don't blame him either, she used drugs while she was pregnant with him and his older sister (thankfully they don't have serious problems) and she abandoned him.
I couldnt pick just one I would have to pick both my mom and mother in law. My mom has been there for me through all the bad times and good times. My mother has been there for me also but my mother in law is more my friend than anything. I can talk to my mother in law about anything and everything. I love them both