A few more ideas: I think if you continue the banding along the top it would do loads to help unify the addition with the brick house. Don't use the same fancy molding, just a plain band to go with the simpler style of the addition. Yes to a pediment/eave over the window. It would "cap" it and give it presence. Use beefier trim on the sides of the window so it looks like the trim is supporting the pediment and to make the window/trim/pediment look like a whole. More substantial trim around the garage and on the corner of the addition. Splurge for a pretty garage door and pretty lamps. I didn't care for the window box. It didn't look like a graceful length to my eye, and the black was distracting. If you still want a window box, paint it white to make it part of the window/trim/pediment element. I also found something odd about the way the siding goes all the way to the concrete (or maybe it just looks that way in the picture). If you had a little foundation showing like over in the brick section, that would also make the addition look connected to the main house. I've drawn in a "foundation." Others had wonderful landscaping ideas, especially about balancing the plants and putting a planter or trellis under the octagonal window.

I would landscape it the opposite of what you have. Right now the bushes on the right are hiding an attractive feature of the home, (the arches on the portico) and not covering the weird one (the bricked up windows). I would tear out the bushes on the right and do something on the left. I'd be inclined to highlight the curves by doing an espalier or something against the wall, but that is just me, I don't mind futzing with plants. You might want some big shrubs to cover it up. Remember they will start small but pick one that will fit the space when mature.

The way I see it, the blank wall has one possibility and that is as a backdrop for a proportionately sized planting arrangement. The most likely possibility of plants that fit would be an arrangement of 3 small, multi-trunk trees (12' height ... made of what would otherwise be known as large shrubs) where two are at the back row (a few feet from the wall) and the third is centered between and in front of them, as a 'front row.' They would be limbed up to half their total height and sitting in a bed of groundcover that is substantial in size. In fact, the bed would also encompass the existing tree. If you'd imagine a 12' circular bed with the existing tree centered in it, that would be a major part of the bed. Then, in line with that same tree, extend the front edge of the bed straight over to the drive and parallel to the house front wall, fine tuning the details as to what makes sense. (Thus, the front-to-back depth of the bed would be roughly equal to the same distance that the tree is in front of the house, where that measurement is made 90* from the house facade.) The multi-trunk trees would be spaced such that the the width of their finished form fits comfortably within the confines of the brick wall width, excluding the entrance area. It seems that an effort is being made to obscure the entrance door. I think this is opposite of what the goal should be. I'd remove whatever screen is in front of it and widen the drive with an abutting walk that goes directly to the entrance area. There ought to be 25 square feet of seasonal color planted left of the entrance door.

OK Scott, since you just became the homeowner, I have a change of advice. While it is great that you are focusing on the curb appeal, I suggest you should direct your attention to the heating and building envelope since this will be your first winter in the house. Although it looks like the rehabber did a thorough job, many skip or skimp on the stuff that can't be seen, like aging insulation (or 100 years ago NO insulation), drafty corners, rooms that are burning hot and others that are freezing cold, etc. Save some $$ for resolving this. But I wholeheartedly agree that now is the time to plant a tree or 2, but I will reiterate that unless you are in a Sun State, really good windows remove the need for shade from trees, awnings, etc, and it looks like that work got done already. The trees really are only needed to dress the lot, unless your interior walls were burning hot from afternoon solar exposure. As an aside, I profess to know nothing about early 20th century interior surfacing techniques in Ohio, but I wonder if that heavy stucco was a more modern fast fix to deal with the naturally imperfect walls that come with building technologies of the time. IOW, I personally would look into whether that stucco should even be there at all.