I use Jolteon as my lead in about 90% of all my teams.
Timid@Leftovers
252 SpA/Spe
-HP Ice
-T-Bolt
-Sub
-Baton Pass
Jolteon is just my favorite pokemon. ever. I use him as a lead regardless of how the metagame shifts. Sometimes he works wonders, sometimes he gets pwned, but I use him...