What I sometimes use a a lead:
Accelgor @ Focus Sash
Ability: Sticky Hold
EV's: 4 HP / 252 SpA / 252 Spe
-Energy Ball / Giga Drain
-Hidden Power Ground / Focus Blast???
A lot of people don't expect the acid spray and you can force switches really easily.
Turn 1 Acid Spray, breaking sash and giving -2 SpDef, next turn hit them with SE move.
If you can manage to live without using the sash, Giga drain might be nice to get back to full HP.
It outspeeds most things that aren't scarfed.
~HG Friend Code: 4383 5683 9907
~White Friend Code: 0690 4629 9853