Centering DIV with CSS

Liquid:
.container{margin-left: 10%; margin-right: 10%;}

Fixed (including ie4-6):
body{text-align: center;min-width: 750px;}
.container{margin-left: auto; margin-right: auto;width: 750px;text-align: left;}

Resources:
CSS Centering - fun for all!
Centering a Div