I can't answer the memory question definitively, but I think as long as you have enough for the scene, then other factors will probably take precedence. My laptop with 2GB RAM and a dual-core 2.1GHz Pentium is a good 50% faster at rendering my avatar than the system I used earlier in the thread, which had 4GB RAM but only a single-core AMD processor rated at 2.8GHz. Both were running 32-bit XP. A more complex scene may well give different results.

Moving on to camera moves, it does seem that the renderer still refers to off-camera objects in some way. Renders sped up if the camera pointed away from the complex parts of the scene, but were slightly faster still if those objects outside the camera's field of view were made invisible.

Also, my habit of surfing the net while waiting for a render to finish adds time as well. But I knew that already. :)