What IP do i use for my Bukkit Server?

So I just created a bukkit server and it works fine the console works.
But what ip do I use do I use the ip from whats my ip for people from all over the world to join or is there a different one because I see servers like the hive that have a special ip that isn't numbers.

Also I ask this because someone said in a youtube video that you don't want to give this ip out to random people to join your server because they can do all sorts of things whith it? is that true?

So I just need to know what ip to use the one from whatsmyip or a fancy one from no-ip.

and if it means I have to use no-ip to do it how to I get DUC to regognise that my server is the one to apply the ip to?

 

You can use one from no-ip or register a domain name and use it for your server IP.