I can't give an informed opinion on PTA or Aronofsky as I've only seen three of their films combined (Boogie Nights by PTA, Requiem for a Dream and The Wrestler by Afonofsky), although I really liked all of those three.
For the rest, my pick of the bunch is Tarantino. I've seen most of his films (all except My Best Friend's Birthday and his Four Rooms segment), and I've loved all of those except one (Death Proof, which I still liked).
As for the rest;
I've seen all of Fincher's directorial work, and I didn't care much for Alien^3, but I loved Seven, Fight Club and The Social Network, and thought the rest was pretty good.
I loved Scorese's Goodfellas, The Departed, Shutter Island and The Wolf of Wall Street, liked Taxi Driver, The Color of Money, Casino, Gangs of New York and Shutter Island, and I thought The Aviator was okay, if a bit long and had some boring sequences. Haven't seen the rest of his directorial work.
Haven't seen Cameron's Xenogenesis, Piranha 2 or his two documentaries (Ghosts of the Abyss, Aliens of the Deep), but I've loved (Aliens, The Terminator 1+2, True Lies) or liked (The Abyss, Titanic, Avatar) the rest of his films.
I wasn't even born when Spielberg made about half of his films and I haven't seen a lot of his earlier work. Loved Indiana Jones 1-3, Jurassic Park 1+2, Saving Private Ryan, Catch Me If You Can and Munich, liked E.T., Hook, Schindler's List, Minority Report, The Terminal and Lincoln, didn't care much for A.I., War of The Worlds or Indy 4. I'm about to put on Close Encounters of the Third Kind now, so hoping that falls into the first category.
In any case, in my limited time as a film enthusiast (I'm 27) and with my limited knowledge of film history, these five are all definitely in my top 10 list of all time, probably all in my top 7 or 8. Also, writing this post has made me make a list of DVDs/BluRays I'm going to buy in the near future.
