I love any of the happy endings.
Like when a PT pup(or cat!) that had been missing finds their way back home. Seeing an update that one of PT's very own made it back to their owner safe and sound is probably my favorite thing to log-on and see! The first ones that come to mind is Glacier's Delta and Kfamr's Kiara, but I am sure there are many more that I am forgetting at the moment.