1) Lucario @ Choice Specs ( Non - Mega )
EVs - 252 Sp. Att./252 Spe/ 4 HP
Nature - Modest(+Sp. Att; -Att.)
Aura Sphere (STAB) - For those irritating Double Teamers and Minimizers. Offers a good stab of 90 x 1.5 = 135
Dragon Pulse - This should take care of most Dragon-types in one/two hits due to the Choice Specs
Flash Cannon (STAB) - A good STAB move(80 x 1.5 = 120) and also good coverage. Good for lowering Sp. Def.
Dark Pulse - Good for OHKOing/THKOing those annoying Ghost-types because Aura Sphere won't effect them.
2) Lucario @ Lucarionite (Mega)
EVs - 252 Att. /252 Spe/ 4 HP
Nature - Adamant (+Att; - Sp. Att.)
Close Combat (STAB) - What's better than bombarding the opposition with a swift fury of punches. BP = 120 x 1.5= 180
Extreme Speed - To outspeed any Pokemon (Priority +2).
Bullet Punch (STAB) - Again to OUTSPEED
Blaze Kick - Unusual, but I like it. Useful for Grass-types.
3) Lucario @ Lucarionite (for extra speed)
EVs - 100 Def/100 Sp. Def./252 Spe/56 HP
Nature - Jolly (+Spe;-Sp.Att.)
Roar - This set is paired with a Pokemon which can learn Stealth Rocks and Spikes.
Copycat - After using Roar, use Copycat(which will copy Roar).It ignores Priority.
Power-Up Punch - To take care of the last Pokemon.
Substitute - For protection.
All of these Lucarios have Steadfast (Ability). Lucario is awesome and I recommend it on any team.