My loadout for my Damage Ice is Wintry Tempest, Frost Blast, Avalanche, Resonating Gale, Impaling Ice, Blizzard.
I like Wintry for boss fights to set up big damage with my weapon, Frost Blast is good for nuking crowds quick, as well as Resonating Gale for a quick little AoE damage burst and a quick damage boost as it's an instant cast. Don't really like Avalanche much so I'll likely get rid of it soon for something else.
Impaling Ice is your boss killer, as when they're down to 1/3 or less it does double damage on top of it's nice damage already and it has a 1-second recharge. Get a Controller to top you off once or maybe twice and you can nearly drop that last 1/3 by yourself in half a minute.
Blizzard is mostly for damage and getting enemies Encased quick in case I need to burn some quick damage on larger groups getting out of control with it, and it gives Resonating Gale some bonus damage too IIRC. I don't really need it all that much, but it helps in a pinch, usually in Raids.
Lastly, I ended up switching to Bow, because it's a lot easier to lay down damage if I'm fighting from a range and not getting blasted with boss AoE every few seconds. There's much less worry with a good team that has the tank able to hold aggro very well and you're safe from a lot of the moves.
Might is for boosting Powers, Precision is for boosting weapon damage.
Unless I'm seeing it wrong, Might seems the better choice later on. Not only is it worth more per point at higher levels, you can get lots more of it, and wearing Damage gear will still get you a decent amount of Precision as well.