Michael Adams (mdawaffe)

Just One Category will cause WordPress to display on a category archive page 
only those posts which are direct members of that category, i.e. this plugin 
will exclude from that category page all posts which belong to any of that 
category’s subcategories but do not belong to the category itself.

Just One Category

On a category's archive page, displays only the posts directly in that category, not in any sub-categories.

paulperkins

The Bimblers Exclude Posts plugin is used to exclude selected post categories from the main loop.
This might be useful if you use WordPress posts to author content which should not be listed on the front page, 
but you still want to utilise the features of a WordPress post type and do not want to go to the effort of 
setting up custom post types.
At this point in time, the post categories excluded by the plugin are hard-coded in the main class file. A future 
version of the plugin will include a configuration GUI.

Bimbler Exclude Posts

Excludes selected posts from the main loop. Filters by post category.

Just One Category vs Bimbler Exclude Posts