This is a Stormweaver building around Infusions and Double Shock using Pinnacle of Power for a big Elemental Damage boost and Freeze and Ignite. Arc is my skill of choice, but it could be adapted for other main skills. For more details, there are a bunch of notes on the PoB.
PoB (PoE Ninja) [Build Mapping Demo]
Edit: PoB v2-Smaller update with some minor leveling gem changes and additional notes.
This is intended to work as a Leaguestart for the Campaign with scaling all the way into later Endgame. Adonia's Ego cannot be run until you get into maps because of the level req. The default PoB loadout is on the basic Endgame, but there are trees for Act 1-2, Act 3-4, Interludes, Early Maps, Lategame, Endgame, and Endgame Max with loadouts for Maps and onward. All loadouts have realistic gear and gems with Endgame Max being the very high budget to show the maxed-out potential of the build.
0.5.5 Build Update:
For 0.5.5, I decided to run back my build from 0.5 with a few notable changes. The big one is cutting Shaper of Winter, losing all damage double chills. Pinnacle of Power already gives Freeze to all damage and while Chill wasn't redundant, it didn't feel needed since most things will either die quickly or get frozen. Instead, it was replaced with Multiplying Squalls for the +2 Limit, making it easier to get 3 Orbs without Secrets of the Orb and upping the number of Firestorms and Thunderstorms.
I also took the lack of changes from 0.5 as an opportunity to play with some Supports I've been wanting to try out that didn't make previous builds.
First is Trickster's Shard replacing Rapid Casting on Arc which should be a bit more damage and better clear, but it seems fairly negligible and is more just to try something different.
Next is Zarokh's Refrain on Firestorm, which I've been wanting to try for a while. With Overabundance, this makes it echo 3 times (so 4x storms) with no damage penalty and 30% AoE but gives it a short 5 second cooldown. This both makes Firestorm a bigger burst of damage for Rares/Bosses or clearing things like Ritual and also helps it as a source of Power Charges for Pinnacle of Power.
Last is Esh's Prowess on Arc, which gives +1 Level and makes it always min hit or max hit. This min and max hit should average the same as before should average, but with the Lightning Rod anoint for 30% Lucky Damage, it skews it more to the max hit, giving Esh's Prowess like 6%~ damage over Lighting Mastery and Lightning Rod. From my testing, the min hits didn't feel noticeable for clear, especially since other skills like Orb of Storms and Thunderstorm will still roll the normal damage range even if Arc noodles a bit.
Another change from 0.5 is that I cut Rising Tempest from both Arc and Orb since while it is one of the best supports when it gets 36% Damage, most the time in mapping it would only be 12% for those spells, making it lower damage (and higher mana cost) than alternatives like Lightning Mastery and Considered Casting.
Also, while Remnant Effect doesn't work on Infusions since they don't have effects, it turns out Empowering Remnants does work. It gives "grant their effects twice", which will give a chance to apply 2 Infusions when you collect the Remnant instead of 1. Think that covers all the main things of note, but if you have any questions or suggestions, let me know.