Though he can not learn solar-beam he has all the desired resistances, he has Charge beam as an electric move, he benefits from the sun with Flamethrower/Fire-blast and has Earthpower for a strong Special Ground type move. He has Great S.Attack and is fairly bulky. He is OU.
Latios does not have a strong Special Rock or Ground move but: He has the desired resistances, Thunderbolt, Solar-beam, Great S.Attack, Bulk, and is OU. Latias works too but has lower S.Attack.
Although not resistant to Ground and does not benefit so much from the Sun and lacks S-beam it is Bulky(And has Cosmic-power), has Power-gem, Thunderbolt, and is OU. Starmie can perform as a Rapid-spinner as well and does not really need water type moves to perform well.