Chickens without a doubt. Simple to care for, great fun to watch, personable, eggs, meat if you are so inclined, great manure for compost/garden, "self-seeding" (they create more chickens), they clear areas for gardening while fertilizing, eat lots of bugs. I love having chickens.
As far as plants, autumn olive and comfrey are my favorites. Autumn Olive are easy to propagate, have very good berries for humans, chickens LOVE the berries, they fix nitrogen, they make a nice habitat for small birds, they are easily coppiced, and they are very attractive.
Comfrey makes great biomass, it's good livestock food, it has medicinal properties for humans, it acts as a rhizome barrier, it brings up nutrients from deeper than other plants can go, makes great
compost, is an awesome chop and drop plant, it houses hundreds of spiders over winter, the bees LOVE the blossoms, they are very attractive plants, are great living mulch plants.