Hook,
Initially I felt a subconcious need to keep my head fixed straight ahead, as if looking around would somehow "uncenter" the 12 o'clock view.
Once I got distracted with the business of flying this disappeared and it became quite natural.
Be sure to map the Pause and Recenter functions to your controller. As the experts above have said, you're probably going to Love TrackIR.
So does 'Hook' mean you were a Navy type, or maybe a pirate?