Manaphy @ Life Orb / Leftovers
/ 252 HP / 252 Special Attack / 4 Speed /
/ 252 Defense / 252 Special Defense / 4 HP /
One's a little less bulky, but more flexible in sweeping. The other EV spread is pure bulk, and is a monster with Aqua Ring. Make sure it holds Life Orb or EV Spread #1, and Leftovers for #2.
A bulky Life Orb Sweeper that can switch into a lot of stuff. I haven't used Manaphy a whole lot, but I've played against a few of them, and my God, they're bulky.
This set will hit pretty hard hard (With Life Orb or Tail Glow boosts), and OHKO all OU Dragons like its nothing. For neutral damage, you may need to boost, but with huge bulk, Aqua Ring, and (possibly) Leftovers, you'll have lots of set up and sweep.
This is truly a jack of all trades set that is extremely versatile. Just watch out for fellow Bulky Waters such as Vaporeon, Suicune, and Lantern.