Landorus-T is a very good Pokemon atm, and one of his best sets is:
Landorus-Therian (M) @ Leftovers
EVs: 180 Spd / 252 Atk / 76 HP
- Rock Polish
- Stone Edge
- Swords Dance
This set really makes him into a very fast and dangerous sweeper. You can boost based on whats needed, Swords Dance for slower bulkier teams, and Rock Polish for faster more offensive teams. If you can get both boosts in, this guy becomes very hard to stop. Earthquake + Stone Edge gives good coverage and helps hit the opponent really hard. Intimidate is also a great ability for Landorus-T, making setting up a lot easier.