vertical-align: middle; fungerer ikke i DIV

HTML:
<div class="divCon1">Mellemnavn</div>
<div class="divCon2"><input type="text" ..... class="input"></div>
<div class="clearboth"></div>

CSS:
.divCon1 {
float: left;
height: 23px;
width: 130px;
vertical-align: middle;
padding: 0px 0px 0px 20px;
}
.divCon2 {
float: right;
width: 30px;
height: 23px;
vertical-align: middle;
}
.clearboth {
clear: both;
}
.input {
width: 175px;
height: 17px;
font-size: 11px;
line-height: 17px;
vertical-align: middle;
border: 1px solid #000;
padding: 0px 0px 0px 5px;
background-color: #f6f6f6;
font-family: verdana, helvetica, tahoma, sans-serif, arial;
}

Hvorfor centreres indholdet ikke? Ydermere, i FireFox er cursoren placeret oeverst i textboxen .....?