Before recently, I usually just threw together any old team for the battle tower, and usually did ok. But now I've decided to create a "proper" team, with a strategy which will (hopefully!) give me a decent reward. So without further ado, here's the team:
Changes will appear in red.
The Lead:
Wobbufett@Leftovers
Ability: Shadow Tag
Nature: Calm (+Sp. Def, -Atk.)
EVs: 28 HP/228 Def./252 Sp. Def
IVs: 25/4/31/3/31/9
Encore
Mirror Coat
Counter
Safeguard
Originally a Shuckle, Wobbufett outclasses it in just about every way. A slightly higher Speed (and I mean slightly), I can outrun some of the earlier rounds' leads, getting Safeguard up instantly, or can always go the safe route and Encore what will hopefully be a set-up move. Counter and Mirror Coat make Wobbufett so much more useful than Shuckle, as it can actually get the kill fairly quickly, especially with encore, whereas Toxic Stall took much longer. Shadow Tag is also more useful for the rare times that Battle Tower trainers actually switch.
Sweeper #1
Garchomp@Lum Berry
Ability: Sand Veil
Nature: Jolly (+Spd, -Sp. Atk.)
EVs: 4 HP, 252 Atk, 252 Spd.
IVs: 22/31/8/2/11/31
Substitute
Swords Dance
Outrage
Earthquake
Once again, Empoleon was outclassed. Garchomp is an excellent Sweeper, especially benefitting from Wobbufett's disruption of the opposing lead. I can stick up a Sub, then proceed to Swords Dance. Garchomp, being the epic Uber that it is, can OHKO almost anything after two or three SD's. Outrage and Earthquake are simple but powerful double STABS, whereas the Lum Berry furthers Garchomp's sweep by getting rid of confusion after Outrage.
Sweeper #2
Tyranitar@Life Orb
Ability: Sand Stream
Nature: Adamant (+Atk, -Sp.Atk)
EVs: 252 HP, 252 Atk, 4 Def
IVs: 25/31/25/10/7/7
Payback
Stone Edge
Earthquake
Dragon Dance
Another pokemon that can take advantage of Encore, Tyranitar can either set up using Dragon Dance or hit hard with STAB Payback on the occasions where the move Encored is a Speed-boosting one, Dragon Dance being the more common option. Stone Edge is also good STAB and hits the Flying-types that Earthquake can't. Earthquake finishes the moveset with an excellent hit.
So that's the team, I'm completely open to change so please tell me if anything's wrong :)
Changes will appear in red.

The Lead:
Wobbufett@Leftovers
Ability: Shadow Tag
Nature: Calm (+Sp. Def, -Atk.)
EVs: 28 HP/228 Def./252 Sp. Def
IVs: 25/4/31/3/31/9
Encore
Mirror Coat
Counter
Safeguard
Originally a Shuckle, Wobbufett outclasses it in just about every way. A slightly higher Speed (and I mean slightly), I can outrun some of the earlier rounds' leads, getting Safeguard up instantly, or can always go the safe route and Encore what will hopefully be a set-up move. Counter and Mirror Coat make Wobbufett so much more useful than Shuckle, as it can actually get the kill fairly quickly, especially with encore, whereas Toxic Stall took much longer. Shadow Tag is also more useful for the rare times that Battle Tower trainers actually switch.

Sweeper #1
Garchomp@Lum Berry
Ability: Sand Veil
Nature: Jolly (+Spd, -Sp. Atk.)
EVs: 4 HP, 252 Atk, 252 Spd.
IVs: 22/31/8/2/11/31
Substitute
Swords Dance
Outrage
Earthquake
Once again, Empoleon was outclassed. Garchomp is an excellent Sweeper, especially benefitting from Wobbufett's disruption of the opposing lead. I can stick up a Sub, then proceed to Swords Dance. Garchomp, being the epic Uber that it is, can OHKO almost anything after two or three SD's. Outrage and Earthquake are simple but powerful double STABS, whereas the Lum Berry furthers Garchomp's sweep by getting rid of confusion after Outrage.

Sweeper #2
Tyranitar@Life Orb
Ability: Sand Stream
Nature: Adamant (+Atk, -Sp.Atk)
EVs: 252 HP, 252 Atk, 4 Def
IVs: 25/31/25/10/7/7
Payback
Stone Edge
Earthquake
Dragon Dance
Another pokemon that can take advantage of Encore, Tyranitar can either set up using Dragon Dance or hit hard with STAB Payback on the occasions where the move Encored is a Speed-boosting one, Dragon Dance being the more common option. Stone Edge is also good STAB and hits the Flying-types that Earthquake can't. Earthquake finishes the moveset with an excellent hit.
So that's the team, I'm completely open to change so please tell me if anything's wrong :)