Skarmory won me a lot of matches. If you want an all-around lead I'd recommend Aerodactyl, but Skarmory is a freaking beast.
Set up Stealth Rock, and then decide whether you want to stack Spikes or Whirlwind your opponent. I once won a match by SR+Spikes+WWind. Just that. Imagine the horror. Of course, the opponent wasn't experienced much, but still. Roar/Whirlwind not only kill any attempt at setting up, but makes the new comer gets beaten with either SR or Spikes or both.
Once, I set up 3 layers of Spikes, Stealth Rock, and Toxic Spikes. All with Forretress. My opponent was doing the same, until suddenly my Forretress used Rapid Spin hahaha :lol I basically won the match then with Drapion. Swords Dance + Night Slash/Ice Fang/Cross Poison.
My god I love competitive Pokemon. I don't care much if I lost. It's just too damn awesome.