I'm having problem deciding myself.

I have a lvl 15 blade user with an emphasis on STR (more than 2:1, but not pure STR), and so far I've only added masteries in the Sword/Blade skill. Eventually I will choose some kind of magic, I guess, but I don't know which one. When I used a bow with my last character I liked Cold, becaused it slowed monsters down and allowed me to pick them off at a distance, but now that I'm building a melee character I don't really know...