The final Pokemon until I get Black Version. Prepare... for... Manaphy!
Surf: Good power, high accuracy, STAB, power increased by both Rain Dance and Tail Glow.
Tail Glow: Increase Sp. Attack, allowing for great power with Tail Glow, STAB, and Rain Dance on the already powerful Surf.
Rain Dance: Powers up Surf, allows for Hydration to take effect mainly for Rest, also stos Sunny Day from ruining Surf.
Rest: Obviously. 100% recovery with no downside due to Hydration.