Hey Everyone, Thank you for the responses. I never thought of installing a buck - that's probably what I am going to do. I actually appreciate the response of fixing the current window and evaluate each of my windows as I address them with this in mind. I like the old glass and understand the advantages of my older wood windows. That being said, some of my windows are simply not salvageable beyond building new sashes and starting over - the cost of which in terms of money and time would, at least according to my analysis, exceed the cost of a reasonably high-quality replacement. Some of my windows are also very difficult to access (I have a few 3 stories high in dormers) making the swap of the storm and screen difficult at best. The owner before me installed aluminum storm windows on some of these, but as far as I can tell they are garbage for the most part. All they did was succeed in causing a lot of damage - those are the only windows in the house (out of more than 40) that have rotted sills and jambs. Anyway, thanks again everyone. I am really thankful to have this forum and others like it. I have been working to renovate my house for the last 5 years and simply could not have done it without your help.

Whether the window is 1/4" out, or 1/4" back, here's the thing. You do not want to be 100% dependent on the caulking alone for the seal above the window. Especially a curved top window. Even silicone will separate with expansion and contraction of siding, windows and aluminum wraps. There is some extremely tenacious caulking available, and I would be sure to use only the very most advanced kind, especially above. But regardless of all that, you should not let this be installed without it being "drip capped", or flashed, up behind the siding 2 inches at least, then out and over the edge of the top of the window. If they are competent at their metal work, they should be able to figure this out and do it. It will be a pain in the neck and take extra time, but it really has to be done properly.

The window trim change would be to Craftsman style. Unless you are doing the work yourself it seems a lot of expense for little difference on upstairs windows. It would, however, be extremely easy to do on your front door as you would only need to change the top board. And you could replace the side lights with solid wood inserts, or you could use textured glass that would obscure the view while still letting light in. While the limestone exterior is very light it has a yellow hue. Simply speaking the easiest way to find colors that work with the warm limestone is to choose a nearby color. That was probably why the trim is green. Since you prefer a modern look, I suggest you keep your siding light and use color only in the trim. Below are two combinations that I like. I darkened the roof color in these pictures.

JudyG Designs, I had planned on adding trim around the windows but now, after looking at that picture again, I may not. The first row of siding is actually a PVC starter board so it'd have to be notched to put trim below all the horizontal sliders. And there isn't a lot of room around the bay windows for trim. I guess I'm indifferent on the trim. What's your opinion?