I'm not sure what the criteria for a "best is the world" garden are, but I've found the Alan Chadwick Garden here in Santa Cruz on the University of California campus to be quite inspirational. (Though I haven't worked there.)
Alan Chadwick (now dead) deserves much more recognition (I guess he didn't write much?) for his influence on sustainable agriculture. He was tutored by the immense Rudolph Steiner of biodynamic fame. The biointensive/French intensive gardening styles that Chadwick championed I certainly would not describe as permacultural in the same vain as I would Fukuoka, but very effective and sustainable in their own way they are.
The plants in the Chadwick Garden, all of them intensely green and vibrant with aliveness, are quite a testament to what a deep and beautiful soil can support. This is a lovely, lovely garden. The incredible tilth here is the product of decades of dedicated labor, intensive and disruptive (think: perpetual double digging of beds). This does suggest only limited applicability of these methods to a permaculture, but also proves that where these methods are indeed applicable, they are so very applicable.
Also, as noted in Rain Tenaqiya's great West Coast Food Forestry book, the Chadwick garden is functionally somewhat food foresty in its interplanting of small fruit trees above and between annual beds.
A quick search and I dug up a clip of the master himself (
http://www.youtube.com/watch?v=jdMeyywc2xo) as well as a cheesily produced tv segment that shows the current garden and some of its techniques (
http://www.youtube.com/watch?v=2_c2qzGLLHc).