Espeon. If you can get it with its Dream World Ability Magic Bounce, all Status moves ie Poison will be bounced back, as well as things such as Stealth Rocks. It is an amazing Pokemon.
Here is a set :D
Espeon (F) @ Light Clay
EVs 252 HP 252 Speed 4 Def
(You may be wondering about baton pass, but it lets you switch without potentially being OHKO'd by common pursuit users such as Tyranitar. Since hard switching has +7 Priority, you can see what the opponent goes into, and then switch in the appropriate check/counter.)