BuddyPress.org

== a comprehensive online listing of all buddypress plugins and their compatibility issues – with WP 3.x and among each others ==

That would a great BP community project if members could/would submit their lists of compatible/incompatible BP plugins. Also would be great if someone could check code of current BP plugins if these were updated to meet this http://bpdevel.wordpress.com/2011/02/24/updating-your-buddypress-plugins-for-1-2-8/

it would be cool if at the very least, something like what Andy Peatling came up with before for previously released BP plugins when BP 1.2 rolled out.

WP.org Forums has some Troubleshooting Tips for those who have issues after upgrading to WP 3.1
https://wordpress.org/support/topic/troubleshooting-wordpress-31-master-list