Use different single template per category

First, you’ll have to create each different layouts you’d like to use. In this recipes, they’re named single1.php and single2.php. The default posts template is single_default.php.
Once you have your templates ready, insert the following code on your regular single.php file. When single.php will be called, this code will automatically include your custom layout based on the current category id. If you need help for getting category ids, juste read this recipe.

TEMPLATEPATH is on the way out …

This is a better way to go