At Lvl 10 take Disintegrate for poke and decent burst damage, take Wave of Force if you feel threatened by the enemy or they have an E.T.C that went Mosh Pit ultimate, though be warned, if you push in the wrong direction it could be fatal.

At Lvl 20 I take Tal Rasha's Elements for some insane burst damage, you can upgrade whichever ultimate you took, for an increased effect, or you can go with the most desired Lvl 20 of all heroes, Archon: Pure Power, you can enter this form on a very short cooldown and it will allow you to cast Disintegrate without cooldown!
WARNING!: If you take Archon: Pure Power, you have to know, that to be able to blink away or use another ability, you will have to first click the Archon active talent again, and only then can you blink away, the problem with this is that the animation has a slight cast time, which will leave you vulnerable for a second~.

At Lvl 7 you can take whatever talent you prefer, Calamity deals a lot of damage, problem is you'll be in melee and vulnerable, but with later talent you will have a shield and shorter cooldown by taking damage.