You can get rid of all the repeated
width="50%" align="left" valign="top" style="background-color: #F3F3F3;"
in the <td> tags, and put one declaration in your stylesheet that will control them all.
Code:
#productDescription td {
    width: 50%;
    text-align: left;
    vertical-align: top;
    background-color: #F3F3F3;
    }