You need to put your text inside an element if you want to position it inside a div. Right now, the text is just part of the div, but if you properly put it in a <p>, as it should be, You could using positioning to place it anywhere inside that div without resorting to padding.
I guess he drives at this,
[HTML]<div style="height:150px; width:200px;vertical-align:middle; border:solid 1px red; position:relative;">
<p style=" bottom:0px; position:absolute;">This text should apear at the bottom of the div!</p>[/HTML]
Hope it helps,
Rawan.