What are some recommendations for mage character builds?

Solution 1:

Good and fun are a bit subjective, but I can tell you what is powerful.

Crowd Control

Crushing Prison - Both good damage and powerful cc, Crushing Prison will remove an enemy from the fight for a long time and even shatter frozen targets. It is invaluable for removing powerful casters.
Cone of Cold - Great as a CC and for Shattering people, but I find the real power of Cone of Cold is lining up my enemies for Shock, Flame Blast, Chain Lightning (assuming you have the mana) This is just powerful dps and you don't have to worry about enemies moving. Since FB is low damage and CL is expensive, often times my combo is just CoC into Shock.
Mind Blast - Every Mage I make has this ability. It is cheap, effective, aoe stun and I cannot imagine skipping it. It'll get you out of many pinches.
Winter's Grasp - Though at later levels it has a low freeze chance (100-enemy level*5), and it doesn't freeze enough to shatter, it is very cheap and is useful for a large portion of the game.

AOE

In the same mind set of CoC into Shock: Blizzard into Tempest. While Inferno is technically a better choice, I often don't have the points to go that far down the fire tree.
Mana Clash - While technically AOE, this spell feels more like straight dps vs Casters. It is worth mentioning that this is the easiest way to get your Heavy Hitter achievement.
Virulent Walking Bomb - More fun than useful in most situations, it still brings heavy Physical damage (but not reduced by armor). A great room clearer.
Chain Lightning - This spell actually comes with a long cast time (2 seconds) so I like to pair it with abilities like CoC and Blizzard. Unfortunately its high cost means it's hard to work into nice combos. I do recommend it though (and really the entire lightning tree).

Solution 2:

Cone of Cold is strong enough by itself that against normal enemies, no other spells are necessary. The cooldown is short enough that you can repeatedly cast it on the same group to keep them frozen without ever giving them a chance to act. If you have more than one mage who can use it, you really only ever have to worry about boss (and revenant) fights. Of course, something like Stonefist can still be a good follow-up for the instant kills.

Sleep is another incredibly useful spell when facing large groups of enemies, especially archers. Its huge range makes it possible to disable the enemy ranged fighters long enough for you to kill the melee ones and run up to engage in a more favorable position. If you go further down the tree, Waking Nightmare can make this even easier.

These choices will put your mages more in a crowd control role, limiting the number of enemies that you have to fight at one time in order to prevent you from being overwhelmed. A team built this way will probably want another character to be the primary source of damage.

Solution 3:

DA is designed that, whatever you choose, you can never go wrong. With that in mind, I'd suggest to take two elemental trees (fire and ice for example) and the heal one (if you are playing with only a mage in the party).

The sleep branch is useful but very mana consuming. Sigils are fine if you bother using them.

Solution 4:

Just finsihing the game myself and I would agree Cone of Cold and Mind Blast, are must haves, Crushing Prison is great and Sleep is very useful (so is Heal for that matter). However no one has mentioned Fireball which is a quick cast AoE which knocks down the enemy.

One of my favorite tactics was to use Fireball as a door opener; simply cast it behind the next door you are going to open and in casting the spell you open the door and almot immediately burn/knockdown all the foes by the door. Only time this doesn't work is if there is going to be a cut scene and the enemies are immune until the cut scene is done.

Other spells I like are paralyze (works against almost everyone) even though I could live without weakness. I like Stonefist for shattering or knocking down foes. Inferno and Blizzard are both good AoEs but slow to cast Inferno tends to do more damage, but Blizzard knocks down. Vulnerability Hex is good if you will be using a lot primal spells/effect. Personally I love the Spirit Healer specialty with group heal and revive both hugely useful (especially if you get Wynne late and dont want to use her in your party). Personally I regret the shapeshifter spec but didn't want to be a Blood Mage (just didn't fit with my character's style) and If I wanted to use weapons I would not have been a mage.

Solution 5:

A few things I haven't seen mentioned yet.

Blood Magic

Drain life instead of mana, giving you one less thing to worry about. You'll almost always worry about your hp anyway.

Works when you want to put a bit of points into constitution
a powerful heal and a chance to control an elite monster while clearing his minions.
Incredible crowd control in the form of Blood Wound

Disables

A full set of disables guarantees that even the hardest bosses will be frozen in place for more than half of the time of the battle. This helps a lot at harder difficulties and makes going through normal and easy a cinch.

From other posts:

Winter's Grasp - quick cast slow
Cone of Cold - Before it was fixed this was ridiculously broken and won the whole game for me on my first playthrough literally. Post-patch this is pretty balanced and yet still manages to hold down virtually anything, even bosses albeit for a shorter period.
Crushing Prison - quick cast disable (works pretty well with grasp)
Mind Blast - when things get out of hand and you find yourself surrounded
Sleep - great for every kind of setup, even as preparation for mass paralysis.
Paralysis - A more reliable form of disable, and from my experience, seems to have a higher chance of success against elites and bosses.
Mass Paralysis - Massive version of paralysis (relied on this A LOT after cone of cold nerf), and yes, still useful against bosses when every other spell is on cd. If you've got another mage, this is a great setup for massive spells, even better than sleep since they won't be able to move even after damage. (Prefer this over waking nightmare most of the time)
Blood Wound - for every creature with blood, this is the best form of disable a mage can get as it also does considerable damage.

I managed to use this uring my awakening playthrough, and here I used two mages. - Mage 1 casts paralysis, mage 2 prepares a blizzard - Blizzard is cast: Mage 1 casts Tempest with Spell Might(Storm of the Century), Mage 2 casts Inferno

All this can also be done with just one mage (except for inferno as it's hard to get any more points there with all the other trees filled up)

That clears just about any mob leaving Nathaniel, a few crushing prisons and grasps to take care of stragglers and if any get too close, there's always a cone of cold waiting for them.