I just attended, on Sunday, a seminar on fall harvesting/winter gardening! Mind you, I am in Zone 8, in the Maritime Northwest.
Root crops (rutabaga, turnip, parsnip), garlic, onions, shallots and radishes do well in the winter.
Eliot Coleman wrote a book called The Winter Harvest Manual
http://www.fourseasonfarm.com/main/b...t2.html#manual
and FOUR SEASON HARVEST: Organic Vegetables From Your Home Garden All Year Long
Go look at his books -- he will probably have more and better ideas, and definitely more wisdom and experience than I.