BuddyPress.org

Boone, I tested and your code works pretty good!

I did two things:

1. Like I wrote above, I created a folder “activity” in my child theme and copied the index.php from the bp-default-theme activity-folder inside. Then I changed in index.php the following line:

<option value="new_blog_post"><?php _e( 'Show Blog Posts', 'buddypress' ) ?></option>

and have this instead of it now:

<option value="new_blog_post" selected><?php _e( 'Show Blog Posts', 'buddypress' ) ?></option>

Now, the Blog-Post option is shown first in the selection.

2. In the same index.php I deleted the no-filter option:

<option value="-1"><?php _e( 'No Filter', 'buddypress' ) ?></option>

That’s it.

You can see it working here: http://tastentango.de