Which is the best or most common VPS Operating System?

I am signing up for my first Virtual Private Server and have a choice of operating systems which are CentOS, Debian, Fedora Core, Suse and Ubuntu.

Has anyone got any recomendations as to which would I should go for?

My VPS experience is very limited although I am a web designer so my general coding is ok.

What is a VPN?

VPN is (Virtual Private Network) were first used by companies to enable their employees to securely access internal systems such as email remotely (e.g. from home or while on business trips). Today they are increasingly being used for personal use by individuals to protect their privacy while online in public places (e.g. when using the wi-fi connection in a cafe) or in a country where the internet is censored / blocked (e.g. China, Saudi Arabia��).