I will always be a fan of the Cluster Arrow skill. With trail of Cinder, i much prefer to go with Loaded for Bears since it is an instant attack compare to cluster bomb. But with the coming nerf of ToC, i might go back to Caltrops and Cluster bomb.

I tried going Ball Lightning with ToC. It was great. I think it is more fun than cluster arrow. The damage is awesome. Here's my build:

Ball Lightning deals lots of damage and is a very great skill for leveling up Paragon.