I have found that some customers just really need all in the screen real estate
that they can get to provide their users with a clean and trimmed down view of a SharePoint page. Or they want to provide a view without all of the options of the LeftNav, instead providing links via a Link WebPart or Content Editor WebPart. 

There is a very simple way to remove the LeftNav from a SharePoint page.

1. Go to the page you want to remove the LeftNav from and select the Edit Page option from the Site Actions.
2. Add a WebPart and choose the Content Editor WebPart.
3. Edit the WebPart and select the Source Editor button.
4. Enter the following code into the Source Editor

<style type=”text/css”>

.ms-navframe
{
display:none;
}

</style>

Click Save and OK, 

Wow look no LeftNav, the thing to keep in mind here is that any of the CSS can be overwritten to the page using the Content Editor WebPart. If you would like this site wide than add it to your MasterPage using SharePoint Designer