You can use contextual selectors and move the vertical-align there. This would work with the p tag, then. Take this snippet below as an example. Any p tags within your class will respect the vertical-align control:
#header_selecttxt {
font-family: Arial;
font-size: 12px;
font-weight: bold;
}
#header_selecttxt p {
vertical-align: text-top;
}
You could also keep the vertical-align in both sections so that other, inline elements would use this.