What about adding functionality to prevent spoofing, as an alternative to disabling display names?

However, for some reason I cannot call the user name from WordPress (with the WP-BB synchronization method).

Is there a way around this?

Thanks CK!

feedback though: - allow the full names to be seen on their profiles at least though

that was just what i was looking for

This way, forum users never have to see the WP backend, and they will have the ability to change their forum nickname.

How could this be achieved?
I'd happily add this myself if I had the PHP know how :P

I didn't go that route since loading the entire WordPress API's a bit heavy for something as simple as this, and slows down my site's page load time a lot. So I made a function similar to what ScottDavis did and went with that.

Not sure if you forgot to mention this, but with at least my setup get_author_name() is not an available function. I created one and put it in header.php:

function get_author_name( $id ) {
$user = bb_get_user( $id );
if ( empty($user->display_name) )
return $user->user_login;
return $user->display_name;
}

[topic.php]
replaced get_topic_author()
with get_author_name( $topic->topic_poster )
replaced get_topic_last_poster()
with get_author_name( $topic->topic_last_poster )

[frontpage.php and forum.php]
replaced topic_last_poster()
with echo get_author_name( $topic->topic_last_poster )

[profile.php]
replaced echo get_user_name( $user->ID )
with echo $user->display_name

and so on..

for post.php - if you want the display_name wrapped in a link you can use this slightly modified version of post_author_link()

function my_post_author_link( $post_id = 0 ) {
if ( $link = get_user_link( get_post_author_id( $post_id ) ) ) {
echo '<a href="' . attribute_escape( $link ) . '">' . get_author_name( get_post_author_id( $post_id ) ) . '</a>';
} else {
echo get_author_name( get_post_author_id( $post_id ) );
}
}

i put the function in my header.php file for now.. until i find a better place for it. then, i replaced the call to post_author_link() in my-templates/post.php with my_post_author_link()

there's probably a better/shorter way to do this, but to be honest, i think i prefer dealing with display_names as a template issue. I mean, shouldn't we be modifying the display_name on the way out of the database instead of on the way in? This way, if i ever decide to deactivate this plugin (as i just did), i am not left with a mashup of WP display_names and bbPress topic_poster_names in my db..