Cutting Back Herbs in Fall

I know I've left it late, but I'll ask the question anyway. At the end of the perenial growing/blooming season, should the plants be cut back, or just left standing over winter? What is the best way to prepare the plant for next year's re-birth?
I have left everything standing for now, but I'm sure there will be several more days of thaw etc, before things here in Toronto freeze solid.

If your plants seemed to be free of leaf diseases by the end of the summer and if you won't be too busy in the spring to tidy up the garden, it might be a good idea to leave the old foliage to catch more snow. In this way you can stop some of the frost heaving that may occur with all the freezing and thawing we get in the Toronto, Ontario, Canada area. You could of course cut things down in the fall and then add some straw for mulch to catch the snow. It is quicker to remove the old straw – if you must – than to do all the cutting at that time.
In the spring you could also add some well-rotted manure to your bed of culinary herbs to give them the extra strength to get off to a quick start in the spring. Do not do so in the fall as it may get new growth in the fall and that would greatly reduce the winter hardiness of your plants.