I certainly don't have the
experience, but I have found the work done by these guys quite inspiring:
http://perennialvegetables.org/.
Details regarding your climate, etc., might also help somebody
answer your questions.
Some "perennials" I am planting this year:
-Rhubarb
-Sunchokes
-Sea kale
I am also on the lookout for
-Edible Hostas
-Giant Solomon Seal
There are many others, and the above might not work for your situation.