That hack will indeed work, but I would recommend use conditional IE comments. It will be cleaner and will only allow IE to run the code you specify within these comments. While its true the hack seems to be ignored by other browsers, using a conditional comment will guarantee it only loads for IE.
Here's an example that would only load this CSS for IE6 and below:
<!--[if lte IE 6]>
<style type="text/css">
#TallLeft {display: none}
</style>
<![endif]-->
Check out this page for more info:
condcom.html
-justin