Here's a special set! Just for something different =)
Rapidash @ Heat Rock / Life Orb
Ability: Flash Fire
EVs: 252 SpA / 4 SpD / 252 Spe
Modest Nature / Timid Nature
- Sunny Day / Hidden Power [Rock] / Morning Sun
- Fire Blast
- Solar Beam
- Hypnosis / Morning Sun
The basic idea is to use him in the sun. If you are not confident you will have any, and it benefits your team, slap a Heat Rock on it and use Sunny Day! Then you can blast away with Fire Blast and Solar Beam at will! =D
Hypnosis is there, well, just to make people mad when you land it, but it's accuracy is super shaky, so maybe Morning Sun is more to your liking, as it works best in the sun you will always have up.
Modest Nature in order to hit harder (you will need it), or Timid if you want to try and land that Hypnosis before your enemy can move, or just make sure the sun is blazing.
If you are already confident in your other Pokémon's weather-setting abilities, or if using a Rapidash for Sunny Day support is just too weird for you, give it a Life Orb for extra damage! This also will free up a moveslot, so if you like you can run Hypnosis and Morning Sun, or replace one of those with Hidden Power for coverage. I suggest Hidden Power [Rock] as it has the best coverage options, as only Hakamo-o and Kommo-o resist it.
Since you are using Life Orb, I would recommend running Timid for the speed, but you can always run Modest if you are feeling you are not hitting hard enough.