Security from what?
Viruses stealing my BTS.
Pretty much any Linux distro will work then. There is only one Linux kernel and the distros are just different ways of packaging, supporting, and maintaining the user experience. The biggest threats aren't OS specific; namely browser plugins. Since Linux has such a small consumer install base it's just not worth the time to write malware binaries for it.
I use the following setups that I consider secure:
For my personal wallet: Ubuntu 14.04 with an encrypted install and a really good pass phrase. It's an out of the box option during install. I don't use that install for anything other that my crypto wallets. No browser plugins, surfing, etc. It goes online, I do what I need to do, and then it goes offline.
For my delegate: Digital Ocean VPS running Ubuntu 14.04. For security it can only be accessed via public key authenticated ssh on a non standard port. Password logins are disabled as is root non console login even with a public key.