Slow

Personally I love slow. Primarily against bosses like pap, gheist, and crow. I haven't tried it on anego since i stopped training my ice mage. (Might have to go try that for fun.) I've never made a firemage so i cant speak to that topic, though from what I understand slow helps them a lot for training, but for a funded ice/lit mage, I would strongly suggest skilling lit first, maxing slow, and only putting 11 points in cold beam. Once you have icestrike its doubtful you will use coldbeam at all. As always, your build depends on what you intend to do with the character and how high you plan to lvl it.