Frost Channeling and Frost Warding are useless. Your mana should last long enough for the duration of the fight. No need for the -15% mana cost. Armor on mages is kinda useless (we have crap all anyway) and that 10% reflect is dependent on if you're facing another mage.
Here's my setup:
http://www.wowhead.com/?talent=of0ibobZZVVGcobxoVqt
Yes I took improved amp/dampen magic (only good if you don't have a healer). I don't know how effective it is, but I haven't respecced in a while now, and I kinda like it.
Basically, the main talents you need from 17/0/44 are Imp Counterspell, Block, Snap, Frostbite, Shatter, Bubble, Pet.
The rest are variable to what you want.