mrmina wrote:what the difference between "static" & "not static"?
which is better

Static IP numbers mean that your IP number does not change.... which makes it easy to access from the outside world....
Think of an IP address as a street number for your house.... If you keep moving it means that if you are elsewhere in the world you cannot send a package home because the number has changed... But if you have an unchanging IP address it means that you always know the correct address... It also means you can do what is called "IP forwarding" so for example you can have a domain.... like
http://www.ksrc.net.au or something and "forward" it to a particular ip address.... which means you can have your own web server, or games server or email server....
It also means you can set up VNC to control your computer from anywhere in the world, and you can use VPN (virtual private networks) securely.
On the bad side of things, if you get banned from a channel on IRC you cant get around it by changing your IP number (well, you can use a proxy server or an IP spoofing app if you know what you are doing).
But basically... for home users you dont need it.....