Aaron D. Campbell

Gives you the ability to simply drag and drop to reorganize your images how you 
want them to appear in your gallery. If drag and drop isn’t your thing, it also 
adds an “Order” field to the images in your gallery, much like pages have, which 
allows you to reorder them to display in whatever order you want. Requires PHP5.
If you are having problems sorting since version 1.0.1 of this plugin, read this:
In order to fix another bug, I had to use the filename as a “handle” to drag by. 
When you move your cursor over the name of the file, it should change to a 
“move” cursor, at which time you can drag/drop the image as before.

Reorder Gallery

Allows you to reorder your gallery images with the ease of drag and drop. Resquires PHP5.

Mateusz Mikos

The current version of the plugin adds the possibility to edit the display order of the posts on the main page, on the category pages and on the archive pages.
Posts can be sorted, among others by title, by type or by update date.
In addition, you can specify whether you want to ignore pinned posts and arrange them in the normal order.
You can also choose how many posts to display per page.

Better Posts Plus

The simplest way to change posts order (and more!) to create your own style!

Reorder Gallery vs Better Posts Plus