Something I'm thinking of trying out:
http://www.wowhead.com/?talent=RZxgGzccuZVA0corzo
has nice things from both worlds, while still allowing u some versatility in what your doing.
Also gives good options for what you want to do in raids, you get the increased dmg from Frostbolts, when fighting Fire immune mobs, and also get the ability to do rolling ignites with Fireball/Scorth