FINALLY got the 100 streak in the Diamond battle tower!  I'm quite happy right now!  I lost at battle 101, but I don't even care, I'm just happy I finally got the 100 streak!  
Well, this is my team,
Garchomp-Adamant-Choice Band
Ev's-252 Atk, 252 Spd, 4HP
Outrage
Earthquake
Fire Fang
Crunch
Basically I just spam outrage and earthquake, I never used crunch, and I only used fire fang for Forretress and Scizor.
Starmie-Modest-Expert Belt
EV's-252 SpAtk, 252 Spd, 4HP
Surf
Thunderbolt
Physic
Ice Beam
You're standard Starmie, I would switch Starmie into any water pokemon that I thought would ice beam Garchomp and Thunderbolt to kill it.  Nothing else really needed to explain here.
Metagross-Adamant-Life Orb
EV's-252 Atk, 130HP, 126 Spd (I'm not positive about this, I don't really remember what  spread I used)
Meteor Mash
Earthquake
Hammer Arm
Explosion
Metagross was the deal breaker so many times!  I would switch Metagross into anything that threatened Garchomp or Starmie, it had enough HP to withstand 2 hits from just about anything except fire, which I would never switch it into.  It would kill most anything with Meteor Mash, EQ, or Hammer Arm in 1-shot.  Depending on how many pokemon I had left, I was more than willing to sacrifice Metagross and use Explosion on the next pokemon they would send out, which was a OHKO every time!  And after that it was pretty much over!
I lost on 101 to a major hax!  Lead Gengar, which I'd seen quite a lot, and never had any problems with it, it uses shadow ball, garchomp survives with a little over 1/2 health, outrage, and Gengar is dead.  Well I got hit with a crit hit shadow ball and it one shot Garchomp.  Can't bring in Starmie, so I send out metagross, he uses shadow ball, does like 2/3 damage, meteor mash kills it.  Sends out Togekiss next, I use meteor mash, takes it down to red, aura sphere and I'm dead.  Starmie is last now, I use Thunderbolt and Togekiss is dead.  Sends out a scizor last and I'm screwed!  I use Surf, doesn't kill it, X-Scissor and I'm dead and out!  No crit hit shadow ball and I run over that team, but ohh well, it did the job and got me my 100 streak!
Here's the picture, I think you may have to right click and open it in a new window to be able to see it, but it's there!