Re: Fiberglas Window good for a Bathroom Shower?
I would go with an aluminum, mostly because I hate vinyl windows and doors because they generally don't operate smoothly.
Hopefully your window is above the shower area, windows within the shower are notorious for leaking into the wall. If you've got a window within the shower area, then I would recommend reducing it's size and get it above the tile, since this is a complete remodel of the bathroom and you'll have access to the studs.
For the tub I would recommend cast iron first, it is the most durable. Enameled steel aren't bad, but they do chip when things are dropped in them. I'm not a fan of fiberglass tubs because the gloss coat does wear out and then the porous fiberglass is exposed, which will collect dirt and body oils. IMHO, fiberglass is a little harder to keep clean than enameled tubs, but this is really mostly a matter of personal preference.
I will second the recommendation to visit the John Bridge forum for tile advice.
I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!