Jack Bristow, asskicking dad from Alias, shown here choking Ricky Gervais to death.
Jack Burton, truck driving action hero with great reflexes from Big Trouble in Little China.
Captain Jack Harkness, time travelling bisexual immortal saving Wales from transdimensional evil in Torchwood.
Jack Skellington, Tim Burtonesque King of Halloween town in Tim Burton's The Nightmare Before Christmas.

I used the picture of Bristow murdering Ricky Gervais to try to swing the vote in his favour a little. Ricky Gervais fans should vote for him too, because he brings him back to life shortly afterwards!