Probably Being John Malkovich. It's such a weird but awesome movie. The scene where Malkovich goes inside his own head is one of my favorite scenes of any movie, it's so bizarre and funny. The cast (especially Catherine Keener) is great too. I do however also love Adaptation, Nicolas Cage plays the Kaufman brothers as well as I have ever seen one actor play two people. Chris Cooper and Meryl Streep are great too of course. So yeah I probably like Being John Malkovich just a little bit more, but the combination of Charlie Kaufman and Spike Jonze can never fail,
BQ: It is my least favorite Spike Jonze movie. It's not bad, but I just did not enjoy watching it too much. There was some stuff (like when he rips the guys arm off or whatever) that I found to be odd and slightly off-putting. There were some things I liked though, especially the visual style and the way the creatures looked. I would give it like 6/10.
BQ2: He is great. he would make my top 30, maybe even if my top 20. He's only made three movies though, if he makes more really good movies then his rank would go up for sure.
BQ3: He might be my favorite screen-writer working today. Every movie I have seen of his I love, especially Eternal Sunshine, one of my favorite movies ever. I will watch anything he writes, I hope he does something new soon.
BQ4: I think Nicholas Cage is a more talented actor, but if someone today told me I have to choose between watching either a John Cusack movie or a Nicolas Cage movie, I'm choosing John Cusack because I'd probably I have a lesser chance of suffering (although neither is in particularly great movies nowadays).
BQ5: I didn't know about it until just now, but now that I read the premise I have to say that sounds like it could be one of the most original and cool movies in a very long time. Awesome idea, I'm excited now.