#1. "RE: What is the best BIF settings on the D700?" In response to Reply # 0
By BIF, I assume you mean Birds In Flight. You will definitely want to use AF-C since your subject will be moving. If you are trying to pick a single bird out of a flock or there is a busy background, I would try either the 9 or 21 point dynamic area. If you are shooting a single bird against the sky, like a circling hawk, you might try 51 point dynamic area since it will always pick the bird as the subject against the solid background. You could try auto-area AF for both these cases, but if the scene is busy, it doesn't always pick what you want as the subject to focus on.
One setting I like to use with AF-C is to set a5 - AF Activation to AF-On only. This decouples the shutter button from focus activation. Using this mode, you can have the best of both AF-C and AF-S-like operation. To focus, lock and recompose you use the AF-On button to focus, release it, recompose and shoot. To get AF-C operation, you simply press and hold the AF-On button. Some people have tried it and couldn't get used to it. Most people who have tried it really seem to like it once they get used to it. Search for AF-On to find old threads about this.