Based on your description, I think I'd spend most of my time in the fun garden.
For starters - I'm lazy. I don't like high maintenance gardens. My garden is wild & messy & has weeds in it (gasp!). I prefer perennials that will come back each year, and will propagate themselves.
There are a lot of plants that will thrive in shade, but won't necessarily bloom as enthusiastically. Expect most of the time for the shade garden to be more green than anything else. I've worked on trial and error for my shady area. Iris & azalea struggled (except for the one azalea by the house, and it's VERY low to the ground, & does not bloom heavily), but the mini rhodedendron has done reasonably well (again, with more foliage than blooms). Hostas grow like crazy, but the blooming period doesn't last very long. Same with lilies. The columbines probably bloom the longest. I have a couple wiegelia, two bleeding hearts, and the rest is pretty much all lilies & hostas & columbines. Sweet Williams and Dianthus make nice little bordering plants and will keep blooming if you dead head them. There is one coreopsis that returns ever year, but is honestly kind of unenthusiastic. It spends too much energy trying to grow to reach the sun, and has none left for blooming, so the flowers end up looking like exaggerated orange eyestalks on a cartoon crab.
In the sunnier area down at the eastern end of the garden I have established the coneflowers. I also have rudebeckia (brown-eyed Susans) and blanket flowers down there, but they have not settled in as well as the coneflowers. One thing nice about coneflowers - once they bloom, the flowers stay for a month or more - unlike the lilies, that are a week and "outta there".
I planted sunflowers, dahlias, and marigolds in the other sections of the retaining wall (it's built like a tall terracing, with a long bed in each of the four sections. Time will tell how well they do, but supposedly the marigolds are not as attractive for deer munchies (which tends to be a problem in the lower two beds). With the exception of the iris and daffodils, everything out there is an annual. We're trying to decide what perennials to put out there. The only problem with those beds is that they are a loooooooong way from the spigot, and those hoses get HEAVY.
