I play a "try and get to me" frost mage. I used to have an "oh, instant wool" mage, but the poorly built arcan tree finally got to me. Frost is just aggravating. I don't put any points in fire or arcane, because I will still have very good skills either way. I can always ice barrier and go arcane explosion. There are not that many frost immune mobs out there. Those that are frost immune still have to deal with my damage mitigation. Ice block always works.
Fire is nice, but frost is sweet. "So you have combustion, that increses yoru crit rate once every 3 minutes?" "Every time my target is frozen, my crit rate goes up 50%." (well, by 60 it will, I invested in higher crit damage before the crit frequency. Not sure it was the best choice, but the mental math says that 50% more crits is the same as 100% more crit damage.