The current bay looks perfectly nice with the colonial style exterior. The advantage to this angled bay versus a box bay in your case is that it distracts from the fact that the bedroom window is not centered above the bay. Cant see how the walls under the bay are treated, mine are plywood with an applied moulding, I prefer ‘shaker’ panels if possible.

You can repeat this style with a metal roof if you want that. I think the style is fine but a more boxy one would work as well.

If the grilles on the majority of the rest of the windows are not removeable then slightly changing the configuration of the new bay to have a picture window in the center and grilles only on the top portion of the double hung window would be more modern than what you currently have and still connect with the other windows. If the grilles are removable then taking out the bottom grilles on all the double hung windows would be a more updated look without the expense of replacing every window and would also tie in w/ picture window combo as well.

https://www.pinterest.com/pin/229331806003426946/ 

Sorry, try this one https://www.richmondwindow.com/wp-content/uploads/2016/11/double-hung1.jpg If the grilles are removable you are not limited to the exact same configuration. The metal roof on new bay is a fun idea as well.

May be some kind of

Or no shutters at all.

The only windows really suitable for shutters are the two small ones on the porch. You could get larger ones, as celery pictured, but that's a lot of expense. I'm ambivalent about the bay; you can go either way with that.

Don't just think about the exterior, think about how you plan to address the interior window coverings if you change the window to a box bay.