I prefer having the time listed on the “edit posts” page under the WordPress admin area, instead of just the date of the post. Usually the URL you see this is something like (WP-base)/wp-admin/edit.php. I don’t see a hook to manage this format, so I couldn’t write a plugin. (If there is a hook, please let me know what it is!)
To edit the date and time that are displayed, simply edit line #74 in wp-admin/edit-post-rows.php (line 74 in WordPress 2.51, the line number may be different in other versions of WordPress). Change the portion that says “Y/m/d” to “Y/m/d H:i” and you’ll then see the time listed on the edit.php page. You can use any of the date/time formats defined by php.