My number 1 on the all time scale of greatness:
the humble sweet potato! Or yam as it's known in some countries. It packs a wallop! Simply cut lengthways in four or six, drop a little olive oil and a pinch of rock salt and bake till tender. They're loaded with carotenoids, vitamin C, potassium, and ot course a ton of fiber (highest fiber vegetables: avocado (though some see this as a fruit), beans, broccoli, eggplant (aubergine), lima beans, Brussel sprouts & cabbage (both green and red), carrot, chick peas - garbanzo to you)
The entire list is good and of course includes fruit and vegetable but there may be some surprises there for you as well. Just a few days ago the same author posted the 08 Food Awards Hall of Shame over at the "Great Orange Satan" which should also be required reading.
The good news is I am doing pretty well with respect to the "good food" list. How about you?