It looks like an Oriental-Trumpet lily (OT-Lily or orienpet for short) to me. Young stems on some cultivars in this group often aren't strong enough to carry the weight of the flower, but this often improves with age, sometimes dramatically so as the stems get much thicker. One alternative to avoid some of the staking is to snip of the buds on the small ones at an early stage - this will also help those little ones to grow bigger bulbs with even sturdier stems for next year.
While I love lilies, I'm not sure about having lilies that tall directly in front of a window. One option could perhaps be to move just those blocking the view to whatever new location you decide on? Especially if you are a bit unsure about what you really would like to do with the area, it might be better to do things in small portions. There will always be another time to move the remaining lilies.
