full frost is godly. I haven't tried fire in the later levels but I know I like frost better when I respecced.
The order doesn't matter so much... just think about what you think would help the most at any given point and put the points in that.
/edit also check this guide out
http://wow.allakhazam.com/db/class.html?wclass=7;mid=1165889690174778390;num=66;page=1
Edited, Apr 6th 2007 12:42am by Donimator