I need recommendation on replacement windows. I am about to replace all 19 of the windows in my home. The old windows are original 1976 aluminum builder grade. My house is a two story, brick veneer first floor and T-111 wood siding clad second floor; located in New Orleans, LA.

I think the replacement windows should be:
white, full frame, insulated replacement windows;
low-solar-gain, designed for hot climate. e.g. New Orleans / southern Zone.
AAMA gold label certification - desirable
Energy Star qualified.
performance characteristics: U = 0.5

Are these above listed requirements reasonable - or do they need changes?

Materials - I have no clue. I have heard horror stories about vinyl in this climate. But that is what most folks seems to be pushing. Any recommendations on materials. especially vinyl?

My wife likes Window World. Two of her friends have had their house done and are happy. Any comments?

I have had estimates of $6,000 - $15,000. I Hope to come in at $6,000-$8,000. Is that reasonable?

Please suggest brands and if possible models.

Is it best to pick the window then the installer or the other way around?

How important is it that the installer be around for the expected life of the windows? Or do I just depend upon the manufacturer to help solve problems if the local install is no longer around.