You can disable the left and/or right columns in Admin>>>Layout Settings

Column Left Status - Global
Column Right Status - Global

Be aware, however, that this will also affect the display of sideboxes - some of which display essential links (categories, site information, etc).

I generally disable either right or left, then configure whatever sideboxes I need to display in the available column. This gives me a wider, cleaner space for the display of product info, etc.