if i shoot a music video all on green screen, would i want to edit the video 1st and then do all keying? or what work flow would be best for this?

Edit first for timing and rhythm.

That way you won't be spending lots of time composting material you're not going to use.

Hopefully, you are using a loss-less codec--uncompressed, cineform, canopus HQ. Raw HDV or AVC could be a problem down the road.

Hi Dave. Just be aware of transitions in your edit, straight cuts shouldn't cause headaches but if you are using anything else you might want to bring the clip/instance into AE, insert your background, then take it back into your NLE to do the transition there.

I should add that I rely heavily on Automatic Duck.

That allows me to edit in FCP, then move the composition to AE. From there I can fine-tune, composite, etc.

It's a real time saver!

If the end product is just editing foreground with continuous effects background, then I too would edit first for 'flow' then add the background, but if each shot is 'unique', then I'd probably do each one separately. It depends if the background is somehow linked to the foreground.