Are you having difficult styling category template files? According to Scribu, things are about to get much easier with WordPress 2.9.

But using category-{id}.php in practice is not that fun: firstly, you have to leave a comment in the theme file so that you know what it’s for. Secondly, you have to rename the file for each site that you use the theme on, because the category id isn’t constant.

Check out his post. If you can’t wait for WordPress 2.9, Scribu also gives you a block of code you can use in your themes functions.php file to achieve the same effect.