A few warnings:
Grass is your enemy. Unless you have a large area dedicated to grasses WELL SEPARATED from other areas, grass will make it very difficult to keep a 'neat' look. I did a TON of work in the last year, but one thing I didn't do was make sure I had eradicated the grass in areas near beds and now it is difficult to separate one from the other. I coach my kids soccer teams and am currently working a lot and without much time to work around the yard it's losing some of the shape it had earlier this year.
If you want trees, get them in the ground ASAP and then build from there.
Here's a pic where I eradicated grass:
And pics where I didn't eradicate grass:
It doesn't look bad, but it's not nearly as 'polished' as the side with no grass. It's also been way easier to maintain the side with no grass.