Oh, fun! I would suggest miscanthus gracillimus or m. sinensis - there are alot of different ones to choose from out of these. The bulk of the plants won't obscure the view from the window, though the flowering plumes will be taller. Still not too much to block the view. I have them here in my mid-MI garden. Sometimes the plumes don't mature until late in the season, after frost, but they are a nice architectural addition to the winterscape, when there is so little else to see. Oh, and they grow into a sizeable bush 2-3 ft across. Good bones for your spot without being oversized.
I personally love perennials, so I'd include an accent plant or two of Carolina thermopsis - Carolina lupine. It's yellow, looks like all lupines, but is taller and very hardy here. In your sheltered location, I can't imagine it would require staking of any sort - the stalks are very strong and woody. The leaves would be a nice contrast with the grasses. After blooming, the seed heads are rather attractive for the winter also.
Another grass that I'm going to be starting in my garden this year is Hakonechloa macra - Japanese Forest Grass. Also many varieties and it seems to be in most of the catalogs I've looked at lately. The leaves are wider than some grasses, which lends interest, and some of them get nice fall color, too.
Other possibles: the rudbeckias - any of these are great for a splash of color, and there are more than just the yellows out there. Daylilies are great! And the varieties, colors, shapes of bloom and size of plants are virtually endless, plus they've got all the rebloomers out there now to give a late season flush of color.
So, there are a few suggestions! (I have to stop myself from gushing on...LOL)