Most offensive Zapdos set you see either has Leftovers or Roost on or something else. But here is this Zapdos set that won me many battles by causing massive destruction so many times.
Zapdos @ Life Orb
Trait: Pressure
EVs: 4 HP / 252 SAtk / 252 Spd
Modest Nature (+SAtk, -Atk)
- Thunderbolt
- Heat Wave
- Hidden Power [Ice/Grass]
- Agility
Unlike any offensive Zapdos set, this one runs Agility over Roost, and is perfect for many kinds of things. He can be an early game, mid game or late game sweeper depending on the opponent's team and yours as well. One Agility is enough for Zapdos to either sweep for the win, or cause massive damage to the opponent's team before going down.
For Hidden Power, it really all depends on which you choose. But from my experience, Grass works better in UU and Ice is better for OU, or just depends on how you build your team to counter specific Pokemon. I use Ice the most and works effectively well. Zapdos' best support mainly goes to a Fire-Type like mainly Infernape (with Choice Band or Scarf), or Heatran, etc etc. Though this set is not reliable for rain teams, unless you felt like changing things a little bit. That is all now. Happy sweeping.
Edit: Again, about Hidden Power, if you're gonna use Ice, make sure you have Ferrothorn with you too to go against dangerous threats like a banded Dragonite, Starmie if you're unboosted, Gastrodon, etc etc. If you want to be offensive, go with Celebi. Just make sure you got something to resist ice moves from deadly banded Ice Shard guys or something like that.