It never ceases to amaze me just how many unique voices I hear when I walk through a busy place like a supermarket or a mall. I tend to categorize voices. I'll hear the person in front of me at the check out line interacting with the cashier and think, "Good voice for corporate narrations." Or, "WOW! She's a grown woman and still has a little girl's voice. Maybe animation/cartoons would be a good place for her voice." Of course, to be a successful voice over actor, it's all about what you do with that voice. That's where the acting part comes in.
Recently, I received an invite to audition for a job where they wanted a gruff, drill sergeant type voice. And while I can do an adequate one, I decided to pass on the audition. Days later, I ran into a mid 60's gentleman who started talking to me and had all the characteristics to pull that type of voice off, with a bit of practice and a touch of acting. His natural speaking voice was raspy, deep toned, and had lots of authority in it. I told him he would be the perfect drill sergeant voice over for a script I had received. He smiled at me and said, "Voice over? What's that?"