How to remove some media upload icons from post editor?

If you want to get rid all all media buttons, you can remove the media_buttons action:

add_action('admin_init', 'remove_all_media_buttons');

function remove_all_media_buttons()
{
    remove_all_actions('media_buttons');
}

Since you only want to remove some buttons, I suggest adding an admin stylesheet:

add_action('admin_init', 'my_admin_stylesheet');

function my_admin_stylesheet()
{
    wp_enqueue_style('my_admin', get_bloginfo('template_url').'/css/my_admin.css');
}

In the my_admin.css you can hide the buttons:

/* Hide the buttons you want */
#add_image { display:none; }
#add_video { display:none; }
#add_audio { display:none; }
#add_media { display:none; }