It actually looks pretty good. We had a house built in 1927 with a room added onto a flat roof over the den. There were problems with it structurally, so that might be the first step, determining if you have structural issues. From there you can decide whether to keep and re style the space or not.

If you keep it, maybe new windows would be the most bang for the buck. I would go for a Craftsman look, with windows and roof, maybe like this:

You might take the roof off and replace with roof & fascia/soffit profile that matches the main roof. Would blend into the original a bit more. Also, if you could extend the look of the columns to the roof it wouldn't look so boxy. Looks top heavy to me. And redo the trim at the separation between the two elements so the addition also blends in a bit more. Changing the materials only won't help, you need to physically extend the components of the original to the new.
I suggest get a design professional involved.

i think you got some good advice. all your house needs is some TLC :) it will be beautiful.

The David Phillips house posted by houssaon is a winner!

I agree with Walsh Krowka on this one...love the house, btw...it's awesome.
The problem is not the box, it's under the box. Either beef up the bottom under the box, so that it is slighty bigger or shrink the box up top, change the roof line to mimmick the one to the right, and go from there.
What state is this house in...location wise?

Love your house. I think it's the window. I'd replace it with one more appropriate to the style. Or maybe even two windows.

That second floor front box needs tweeking to get it picking up other characteristics already in the rest of the house. Of course all depends on your budget.

First of all the hip roof and it's short overhangs are wrong. Demo the hip and build a gable with large overhangs typical of the main roof.

Second, both the box window bay on the left and the second floor windows on the far right have a horizontal line element at the window sill. This needs to be incorporated on all three sides of your box.
This can also be emphasized by using horizontal siding (same as the box window bay on the left) band beneath the new contiuous window sill line element. The stucco can remain and should be matched in the new gable area above the window. Also, add tudor trim boards in the gable similar to the second floor windows on the right.

I LOVE your house - you might want to change the 'eye-sore's windows to something more similar to the existing windows? Go rummage in your builders' yards for ones that have been taken out. Then PAINT the eyesore in a contrasting colour - something brite like brick or yellow. Repeat it on that gable sticking out on the right and paint the frames and other woodworks in white. Voila!

It's not that bad ... it's just the white flat siding and the windows that make it look like it was grafted on.

Assuming it's structurally sound, it's just a bit of cosmetics:

1 - make the windows look like the other ones, with divided lights, or add one of those "cheater" mullion panels. Paint them white, like the others, add trim if you need to to make them the same width as the others.

2 - make it look like that bay window at the left, with shingles and a line of white trim just under the windows.

3 - Make the front door more prominent by painting it a light, bright color and add some nice craftsman style

Thanks for replying; so someone IS reading the stuff!! Making a feature of the 'eye-sore' would help solve the issue. I got the impression they want to demolish that part and that would be a shame! And while you are at it - why not plaster the verandah and supports and paint those as well. That will make a statement!!

Fantastic! Thanks SO much to everyone for your thoughtful advice and knowledge! Wow, I'm so grateful for this forum (my first day on this site too!). Great considerations in every comment. I appreciate the time you took to respond, and the photos. Thank you so very much for sharing your feedback. I'm feeling less confused!

I think a lot of comments are on the right track. Give the addition a gable roof over the front to match the look of the gable to the right. Giving the addition the details that match the right side of the home such as; the windows, trim , large overhangs and soffit, will make it blend in well and look like it was always a part of the house.
The key to any home addition is to make it look seamless, as if it has always been there. That rule wasn't followed here, but certainly can be remedied. Other than that, the house is beautiful.