Well, my HeartGold Battle Arcade streak just ended at 53. I got my gold print, so that's the important thing.
The team:
Metagross (The Hammer)
Nature: Adamant
IVs: 23, 19, 31, x, 31, 10
EVs: 252 HP, 252 Atk, 4 Speed
Moveset:
~Meteor Mash
~Bullet Punch
~Earthquake
~Thunderpunch
Suicune (Aquamarine)
Nature: Bold
IVs: 7, x, 23, 22, 30, 25
EVs: 252 HP, 252 Def, 4 SpA
Moveset:
~Surf
~Icy Wind
~Calm Mind
~Rest
Dragonite (Nite Fury)
Nature: Jolly
IVs: 26, 28, 16, x, 28, 31
EVs: 120 HP, 96 Atk, 136 SpDef, 156 Speed
Moveset:
~Outrage
~Substitute
~Dragon Dance
~Roost
I don't hack or RNG, and the Pokemon I use are all self-bred or caught. Obviously, some of their IVs aren't ideal, but they're the best I'll get for the amount of time I'm willing to put in, and I'm more proud when the Pokemon I use are a product of my own effort. The Suicune is Jumpman's monster; it's ridiculously bulky, and can set up on physical and special threats alike, though its bulk is obviously somewhat compromised by its poor HP IV and mediocre defense IV. You take what you can get.
Obviously, the team has a big focus on bulk; I like to use bulky Pokemon who can set up fairly reliably and do a ton of damage after they're set up. This minimizes hax, in a way; the opponent can set up Double Team, but if it can't hurt me all that much when I miss, I'm not that threatened.
The team's gone through a lot of changes; I used to use Latias instead of Dragonite, and it used to be my lead. I wanted it to be a bulky Calm Minder, but I found myself switching it out against almost any physical threat, and its weaknesses to Dark and Ghost were really dragging it down. I switched the lead to Metagross, but Latias was still often dead weight; if I brought it in when I was in a tough spot, it usually wouldn't have the power to do a lot of damage with an unboosted Dragon Pulse. I have to say, Metagross is a surprisingly good lead; it 2HKOs a ton of Pokemon (many of whom it can take out with another attack + Bullet Punch), and it's easy to switch Suicune or Dragonite in on Fire or Ground attacks. I switched to Dragonite because of its better typing, better bulk, and more threatening presence without a boost. The Jolly nature and Speed EVs allow it to outrun Lati@s 1, and it outruns everything except some Choice Scarf Pokemon, Electrode, and Ninjask after a Dragon Dance. The EVs might seem strange, but I came up with the set after I realized my old team had a crippling weakness to Dahlia's Zapdos (Zapdos 4). The EVs give really good special bulk; it's almost never 2HKOd by Zapdos's Thunderbolt (it needs to roll max damage twice, I believe), giving me time to Dragon Dance once, Roost up (taking reduced damage from Tbolt), and start attacking. The special bulk also makes him a great counter to fast special sweepers like Gengar and Alakazam, who can mess up my team if they catch Metagross at low health and don't give Suicune time to set up. I chose the moveset before I realized everyone else was using it, but it fits my purposes very well; Substitute is my answer to OHKO moves; I keep SubRoosting until the opponent is out of Sheer Cold and/or Horn Drill, when I Dragon Dance up and sweep.
I didn't have too many problems in the first seven sets; for the second Dahlia match, I had slowed the board down twice already. I chose to paralyze her team, and she led with Togekiss. I switched to Suicune, set up, and OHKOd her team. Gold print!
I lost the last match primarily due to the board, though partially due to a minor Tauros weakness on my team (as it's too powerful to allow Suicune to set up well, and messes up Metagross with EQ). The board was moving too fast for me to control it well; I tried to burn the opponent's team, but ended up burning my own. I knew I didn't have much of a shot after that, seeing as how my team has two physical sweepers on it who can't get rid of the burn.
The opponent leads with Tauros 4. Metagross comes out, and I immediately switch to Suicune, intending to set up one or two Calm Minds (Resting to allow myself another CM or two). Tauros uses EQ, doing about 70 damage...less than I expected. I use Calm Mind, he uses Return. I underestimated how much Return would do; I may have done better if I had Rested, but a win was pretty unlikely either way. It KOs Suicune the next turn with Return. Now I know I'm dead, but I tried to put up a fight.
I send out Dragonite and use Dragon Dance, since boosting is the only shot I have with that stupid burn. Tauros uses Stone Edge, and Dragonite's down to about a quarter health after burn damage. My genius plan is to use Roost until he misses with Stone Edge, then attempt to KO with Outrage once I've gotten more health back. I Roost for four turns in a row, and Stone Edge hits for all four. Worth a shot, anyway. No crits, and Dragonite's health ends up slightly higher than it was before I started Roosting.
He's out of Stone Edges, so I'm out of options; given the damage he was doing when I used Roost to remove my flying type, I knew Return would be a KO even if I Roosted first. I use Outrage; he falls to about 1/3 health. Tauros KOs with return. Awesome.
I send it Metagross. Since I know I'm screwed, I select the only thing that has a chance of helping me in the long run and use Meteor Mash (hooray for random shots at attack boosts!). Tauros uses EQ, knocking Metagross to about 1/2 health; Metagross's Meteor Mash leaves Tauros with a sliver of health. I finish him off with Bullet Punch, because hey, I might as well go down fighting.
The opponent sends in Blaziken, uses some fire move (I always forget to save the battle video on my top streaks!) and KOs Metagross. Oh well.
Overall, I'm pretty pleased with this run. I really like the team; it has excellent synergy, and it's really easy to manipulate the AI with it (I've beaten Ludicolo 3 with Dragonite by switching to Suicune because I know it'll use Blizzard, then switching back to Dragonite because I know it'll use Grass Knot...five switches and it's out of Blizzards, making it setup bait for Dragonite). I like being able to produce a pretty good run with a bulky team instead of hyper-offense (the battles are more fun for me when I'm switching out Metagross from time to time and allowing Suicune or Dragonite to set up, instead of winning most battles by immediately sweeping the opposing team with Garchomp or Salamence). I really like the Battle Arcade; the board is obnoxious sometimes and the early matches are (obviously) slow, but I also like how the board mixes things up and can add a challenge. I'll probably keep trying for a higher streak later on; I think this team has a lot of potential, as long as I avoid burning them all at the start of a match against a Pokemon that isn't Suicune-bait ;)