If your label is long and goes on multiple rows setting the width and display:inline-block will help.
.form-field * {
vertical-align: middle;
}
.form-field input {
clear:left;
}
.form-field label {
width:200px;
display:inline-block;
}
<div class="form-field">
<input id="option1" type="radio" name="opt" value="1"/>
<label for="option1">Option 1 is very long and is likely to go on two lines.</label>
<input id="option2" type="radio" name="opt" value="2"/>
<label for="option2">Option 2 might fit into one line.</label>
</div>