Add three scenarios and characters when you repost.

Best fictional character to . . .
. . . be at your side after the apocalypse: Jim (28 Days Later)
. . . be at your side fighting a war: Aragorn (LotR)
. . . take over the world with: Abby Sciuto (NCIS)
. . . run your country with: Dr. Lisa Cuddy (House)
. . . be stuck on a desert island with: Sayid (Lost)
. . . marry, grow old and have children with: Radek Zelenka (Stargate Atlantis)
. . . wander the wilderness with: Mahesh "Bug" Vijayaraghavensatyanaryanamurthy (Crossing Jordan)
. . . sail the seven seas with: Captain Jack Sparrow
. . . be your mad scientist: Dr. Crane (Batman Begins)
. . . carry you off across his/her horse into the sunset: Daniel Jackson (Stargate SG-1)
. . . conduct an autopsy with: Donald "Ducky" Mallard (NCIS)
. . . have an argument with: Greg House (House)
. . . discuss the universe with: Larry Fleinhardt (Numb3rs)