Special Attack: 100
Special Defense: 100
Abilities: Inner Focus: Prevents flinching.
Multiscale (hidden): Halves damage taken when at full health.
Looking at Dragonite, one thing immediately pops out: Multiscale. Without any prior damage, Dragonite can take Ice Beams with relative ease. Another thing that shows is good bulk even without Multiscale in effect. All of these elements make it an excellent Dragon Dancer.
However, Ice moves are quite common, as is Stealth Rock, something that will ruin Dragonite. A spinner will be necessary to retain Dragonite's godly bulk. Though Dragonite can take some of the weaker Ice attacks like Starmie's Ice Beam, a STAB Ice attack will do a hell of a lot of damage. Starmie serves as an excellent partner, spinning away hazards and beating a counter to any Dragonite without Earthquake: Heatran.
As for countering Dragonite, any Ice-type with a STAB attack of fair power will end his days, especially if Multiscale is gone. Heatran will also counter any set without Earthquake (and to a lesser extent Waterfall), due to a resistance to many of his attacks, Stealth Rock to cripple it, and HP Ice to outright kill it.
Rather than spend tons of time saying all of his possible sets, I'll just post a link with all of his sets.