Here's my personal aggron.
Aggron Bulky Melee Smasher
Aggron + Rocky Helmet
252 ev's defence, 252 ev's attack, rest of ev's in spec. defence
+Heavy hitting STAB move. (Such as Stone edge, or Iron Head)
Lets take a Gallade/ Salamence.
Gallade's naturally high attack is cut down by aggron's high defence, making a 1-hit difficult, with sturdy preventing fighting from taking it down immediately, and with gallade being 6-7X less weight then aggron, it will be the equivalent of, well, getting stepped on by an aggron with the power 120 based on weight and gallade's weak defences.
Next is salamence. Many salamence are melee based, so using iron defense as you tank damage will bring your damage to almost nothing. when its max, automize until its full, allowing your speed to rival/ surpass salamence, depending on said salamence's nature, with stone edge dealing a 2X 120 move, and if you don't have it using a 100 power heavy slam. using stone edge right away is also helpful if it decides to use a special like flamethrower, as sturdy will not let it get killed off right away, while the bonus spec defense aids in the process.