Plain and simple, this set is awesome and should be on site. I've been using it and it's surpassed my expectations, and it was also in Flareblitz's Round 3, so I'm going to go ahead and do this (I'm pretty sure no one has this reserved or anything).
move3:Hydro Pump / Surf
EVs:104 HP / 252 SpA / 28 SpD / 124 Spe
Why this deserves to be on- site:
-Sets up on and beats many special walls easily (Milotic, Chansey, Registeel, Clefable), and grabs Charge Beam boosts easily.
-With a combination of Subtitute and Charge Beam, you'll beat Chansey and other pokemon that rely on Seismic Toss.
-Meaty substitutes 101+ HP, still remains pretty bulky overall which helps setting up.
-Hits hard with max SpA, very hard after a few boosts, perfect coverage, and is very good against stall and slower teams.
-Surf or even Thunderbolt for a more accurate STAB attack, but Hydro Pump is necessary to beat Chansey.
-EVs: 101HP+ Substitutes and 5 Subs, 124 Spe to outspeed Standard Milotic, max SpA for hittin' stuff
Teammates and Counters:
-Pokemon that draw out special walls: Houndoom, Missy, Moltres, Swellow / Scyther. They will enjoy having Chansey or Milotic out of the way.
-Venusaur stops you, faster physical attackers revenge you easily (DUGTRIO), Registeel w/ Earthquake. Moltres is a great switch into most of your counters.
-Toxic completely screws you over, especially Toxic Spikes.