Easy vet dungeon build (no permapotting, no bar switching needed):
Bar 1 (Destrostaff):
1: Crystal Frags -> use when it procs, else use 2
2: Force Pulse/Crushing Shock (litte more dps vs interrupt, personal choice) -> Spam ability, medium attack weave it
3: Hardened Ward (not absolutely needed when you get no dmg, but very powerful defensive ability)
4: Elemental Ring/Pulsar (for single target encounters you can switch to elemental drain for endless magicka) -> AoE Bombing.
5: Magelight, toggle

Bar 2 (Dual Wield):
1: Liquid lightning -> Strong AoE dot, also use on stationary single target fights
2: Entroy or Surge -> to get the +20% spellpower bonus, always keep buff active
3: Mage's Wrath -> Execute, when boss health <= 20% spam this ability
4: Thundering Pressence -> AoE dot aura and defensive buff, not absolutely needed can use something else here
5: Inner light, toggle

Both Bars ultimate I recommend Overload.
Overload bar:
1: Liquid Lightning -> only dmg skill that's worth casting during overload.
2: Entropy/surge -> to keep the buff active
3: ?
4: ?
5: Inner light, toggle

for overload bar you have more freedom, you can put in more toggles (Pets,Bound Aegis to get very high dps while overload, or put in skills for utility you have no space on the main bar (Dark exchange for magicka recovery during groups). You can also use Meteor as ultimate, but then you have not enough ulti stored for nuking bosses with overload. Or you can also put hardened war there too if you have the feeling your healer/tank could suck ;-).

Edit:
And yes, Dymences Sorc build is the best, the stuff I postet is not much different, I just switched out the second toggle to get more skills in. No switching between single target/AoE needed, that helps for vet dungeon runs. For gear Dymence's setup is top, i'm using that too.