Surprised Arch Linux [1] isn't listed. It's probably one of the most secure distros by limiting the installed packages to a bare minimum. Combine that with App Armour (or SELinux designed by the NSA) with a firewall and basic network monitoring to protect against rootkits. Plus always-on VPN, dm-crypted harddrive, noscript etc.
NSA also released SEAndroid [2] which hardens Android significantly. It's included preinstalled w/ Samsung S4. Although still not very popular and I'm sure not heavily code-reviewed.