hr {
border: 0;
border-top: 1px solid #000;
border-bottom: 1px solid #fff;
border-top: 1px solid rgba(0,0,0,0.1);
border-bottom: 1px solid rgba(255,255,255,0.3);
filter: alpha(opacity = 30);
clear: both;
height: 0;
margin: 15px 0;
}

I mean visually and semantically. Thanks, #NewTwitter.

Updated.

See it live: jsfiddle.net/disinfeqt/Wfntg/3/