What html markups to use for displaying label/value data?

I think the most semantically correct would be <dl>, <dt> and <dd>, since what you’re displaying are effectively definitions of first name, age and e-mail.

<dl>
  <dt>First Name</dt>
  <dd>Dominic</dd>
  <dt>Age</dt>
  <dd>24</dd>
  <dt>E-mail</dt>
  <dd>foo@bar.com</dd>
</dl>

However, obviously, the easiest way to display it in a table is using <table>, <th> and <td>. You could hack together a table-layout using definition lists using something like this:

dt { float: left; clear: left; width: 6em; font-weight: bold; }
dd { float: left; }

<dl>
  <dt>First Name</dt>
  <dd>Dominic</dd>
  <dt>Age</dt>
  <dd>24</dd>
  <dt>E-mail</dt>
  <dd>foo@bar.com</dd>
</dl>

More info on the <dl> tag available here.