Forget annuals except the self-seeding kind. With a few exceptions, I refuse to plant again and again every year.
Shrubs, hardy perennials and bulbs.
Old garden roses are as tough as nails and just go on looking beautiful WITHOUT any pruning.
Overplant, placing those plants closer than sane gardeners believe you can -- if you adopt a "no bare earth" policy, you'll have no room for weeds.
Groundcovers like ajuga form a carpet that will keep weeds down
Laydown cardboard and newspaper to supress weeds. Cover with horse poop. By the time the cardboard breaks down, the weeds will be deader than a doornail.
Shrubs can be anywhere from small to tree size and look great even when not in bloom
Hydrangea
Buddleia (butterfly bush)
Spirea
Wygella (wonderful grandma shrub)
Shrub members of the willow family
Some herbs grow in shrub form and smell great:
lavender
sage
santolina
While you don't want truly invasive plants, those that volunteer are my friends.
lychnis are nice spreaders, self-seed, and have gorgeous hot pink flowers
lambs' ear are delightful (technically an annual, but they are truly no work
day lilies grow like crazy in really dry, difficult places
grasses don't often flower, but look stately and grand, even when dried in winter
(picture 8 feet tall and zebra-striped!! --miscanthus sinensis zebrinus)
You may not be able to get off completely work-free, but I'm pretty darned lazy and had over 1/8th of an acre in gardens at our old place.