Do you want shrubs that produce fruit, offer shelter for wildlife, evergreens, conifers, native plants, flower, fall foliage? How high do you want them? 3 feet, 5 feet, taller? The AC unit, have you considered setting up lattice panels and growing vines on them? Leave room for maintenance work on the house and the AC unit. Also, you need to leave room for access to any utility or water lines in the front yard.