Speaking of Substitute Aggron, a set that I've been having incredible success with in UU is a Magnet Riser:
Aggron @ Leftovers
Rock Head
Adamant (+Atk, -SpA)
128 HP / 252 Atk / 128 Spe
- Substitute
- Head Smash
- Focus Punch
- Magnet Rise
There are so many Pokemon who can only really hurt Aggron by using Ground-type moves, so with Magnet Rise and Substitute, Aggron can take full advantage of this and set up very easily. Claydol, Donphan, Seismic Toss-less Registeel, Regirock, Drapion, Dugtrio, and Tauros are among the Pokemon that Aggron can take advantage off, and they can't break its Subs after its Magnet Rised. From there on its a simple case of demolishing the opposing team with Head Smash, which even without a boosting item will be 2HKOing the vast majority of Pokemon that don't resist it, and using Focus Punch for anything that will be hit harder by it, most notably Normal and Steel-types. Rock + Fighting gets pretty great coverage together, although there are still quite a few resisters of the combo (Toxicroak, Nidoqueen, Nidoking, Claydol).
This Aggron set isn't as easy to throw onto a team as the CBer, but it can be far more effective if you do provide the right support. Sandstorm support is difficult to provide because of Hippopotas' relative uselessness (despite how annoying it can be to face), but it does help Aggron a massive amount by boosting its special Defense, and adds several more Pokemon to the list of things that can't break its subs. It also makes Tangrowth a much shakier answer to this set since it will only gain 25% HP back with Synthesis, and many other walls including it lose their Leftovers recovery, making them easier to beat. Paralysis and TrickChoice support is also greatly appreciated, both of which help Aggron set up against foes (I've found Uxie to be an invaluable partner for Aggron since it can provide both of these things, as well as resisting its 4x weaknesses). Finally, Toxic Spikes can help wear down Slowbro and Quagsire, two of the Pokemon that can deal with this set quite well.
Attack is maxed for obvious reasons, and while it looks like the remaining EVs are simply halved between HP and Speed, the Speed EVs actually serve a specific purpose. They let it outspeed everything up to and including no speed base 65s, notably Walrein, Clefable, Azumarill, Chansey, Donphan, Regirock, and Registeel. The remainder is put into HP to bulk up Aggron's Subs as much as possible.