You don’t need to use the @ sign in front of someone’s name unless you are tagging them in some sort of network (i.e. Twitter, Facebook, Google+, etc.) The reason people use the @ sign on these networks is because it alerts the person who is tagged in the post.
When you use the @ sign in basic emails, it just makes you look silly, and shows that you don’t understand what the sign is meant for. It does not make you technically or social media savvy. Just writing the person’s name without the @ sign will suffice. I think when someone sees their name followed by a phrase or sentence, they are smart enough to know that its directed at them.