Latex: Underlining text along with adjacent white space

To underline text in latex we use \underline{...}.
In cases when we need to underline text and the adjoining whitespace (before and after the text), like in situations of having a filled form, we can use the \makebox command as below:

\underline{\makebox[2.5in][l]{Jane Doe}}

Reference:
1. http://www.latex-community.org/forum/viewtopic.php?f=44&t=5162