I posted this on the hydregion thread, but it would work just as well here:
After hearing some thoughts on Hydregion using a Tinkerbell-esque set, I came up with this set, and after testing it, it works very well.
Hydreigon @ Leftovers
Nature: Modest
252 HP/ 66 SAtk / 140 SDef / 52 Spd
~Taunt
~Roost
~Dragon Pulse
~Earth Power / Flamethrower / U-turn
Works great against Stall and Balanced, Taunt prevents set-up, hazards, status, etc. and cripples many switch ins to Hydregion (Skarmory, Blissey, etc.) Roost keeps you healthy, Dragon Pulse for STAB and good damage all around. The last move is for coverage, or momentum if you like U-turn, which is neat since you can Taunt Blissey coming in and U-turn out to something like Terrakion without fear of being subjected to status.
You can use a more offensive spread, but with this you are never 2HKO'd by Scarf Poiltoed's Ice Beam and never 2HKO'd by Scarf Thundurus-T's Hidden Power Ice (Focus Blast hurts, but you still aren't OHKO'd). You also beat Life Orb Starmie one on one with this spread. 52 Speed nets you that magic 245 number.