Zapdos

Type Tier
Electric / Flying OU
Statistics
Stat
HP
90
383
Atk
90
278
Def
85
268
SpA
125
348
SpD
90
278
Spe
100
298
Name Item

Sleep Talking Zapdos

Leftovers
Moveset
~ Sleep Talk
~ Drill Peck
~ Thunderbolt
~ Rest

Smack everything you can with Thunderbolt or Drill Peck (depending on what will do more damage), Rest when low on health, and continue. Watch out for Rhydon and Steelix.

Other Options

Zapdos is very versatile for a legendary. Thunder Wave can paralyze Zapdos's non-Ground counters (Snorlax, Blissey), making them a little easier to take down. Hidden Power Water can kill Rhydon and crew, but Hidden Power is usually banned. Substitute works well in conjunction with three attacks, it can pseudo-pass both Defenses, and it can Whirlwind (very effective when coupled with Spikes).

Opinion

Zapdos is the best all-around legendary due to its typing. Grass-types, usually the best counters for Electrics, get smacked with STAB Drill Peck. This is a Pokémon that you MUST be able to counter in order to have a good team. Zapdos works well on stall teams, he works well on non-stall teams, he just works. He's got a lot of options, and they're all worthwhile.

Counters

Raikou gives Zapdos a lot of problems - it resists both Thunderbolt and Drill Peck, and is also able to hit Zapdos with a neutral Thunderbolt of its own. Since Zapdos and Raikou usually use Rest/Sleep Talk sets, Raikou will usually come out on top as a result of its higher damage output. Ampharos also resists Zapdos' main attacks, however Zapdos can Rest off the damage dealt to it. Blissey and Snorlax are foolproof counters against Zapdos, and will force it to Rest or switch out every time. Rhydon, Golem, Steelix, Donphan, Marowak, and Nidoking are viable counters so long as Hidden Power is disallowed on Zapdos.