Ok this have 3 answers as well as a best answer but I seem to notice all have down votes I'm guessing because non meet the requirements nor give a good set.
Try this guy.
You asked for attack well walk no further, this guy hits like a truck.
Base 90 def isn't special but it certainly isn't bad, it's typing also gives it many resistances adding to its def giving it a chance to set up with a move like dragon dance.
It has the ability mold breaker which is great when using earthquake on levitating users.
It's speed is also not bad packing a base 97 speed running out most Pokemon but fails at the hands of the base 100 speed dragons that seem to see more use.
It's egg moves are not good but it has a great movepool.
Ok I'm on my iPod so I'm only going to give one set set but I will give you a link to the most efficient sets on smogon.
4hp 252atk 252speed
This set brings you to over 600 atk and over 500 speed after one dragon dance, isn't bad you say but you want more, well life orb increase it's moves by 30% almost insuring a neutral 1hit ko and a possible team sweep.
Other sets you can use include swords dance doubling your attack but then you loose out to dragonite.
Or a scarf set makes a great revenge killer.
A choice band set though is to be feared.
Look Here for more sets.