Since no one responded, try the Landscape Design Forum.

tj

Do you plan to stay in this home for many years? If so, my advice to you is to start with the big stuff. A tree can take decades to fully mature, so it's best to think about them first and worry about the smaller stuff later. Nothing gives a yard appeal and character like beautiful mature trees in my opinion. You certainly have room to add some smaller trees if you wish. I would think about understory trees such as dogwood or japanese maple for the shady area and various conifers for the sunny slope. Your flower beds don't look overgrown to me. They may need some weeding, but there's a lot of nice stuff there. Take the time to figure out what you've already got before adding stuff. The really tall plants in the round bed look goofy, though. I'd find a place at the back of a bed to move those, assuming they aren't weeds.