Maybe I am missing the nuances in this thread, and there always is the ongoing debate about not using nothing but inline in emails... but for us this works fine and renders great in the vast majority of email clients we send to:
<table width="640" cellspacing="0" cellpadding="0" align="center" style="BORDER-BOTTOM: #333333 1px solid; BORDER-LEFT: #333333 1px solid; BORDER-TOP: #333333 1px solid; BORDER-RIGHT: #333333 1px solid; color: #333333">