Mint freezes okay, as does thyme, but for thyme, sage and rosemary, the best thing to do is to cut bunches with longish stems, tie them together and hang upside down in an airy room to dry. Taste will be stronger once dried too. Not sure whether Basil freezes though. My freezer book suggests washing the herbs then packing into small polythene bags and freezing. I find it easier to prepare them and freeze in small 'parcels' of foil, putting only enough in each foil packet to use in one go, and popping the 'packets' into a plastic bag marked with the contents. Chives are really good frozen this way.
From a plant point of view though, don't cut too much off your sage, thyme or rosemary - these are woody shrubs and may be forced to put out new growth if you take too much off, and you don't want that at this time of year, too close to onset of winter. Bear in mind that Rosemary is evergreen, and you can in fact nip out and cut a sprig in the middle of winter and use it rather than freezing or drying it.

Great tips Bamboo. Thanks very much.
JMS1

What a good answer, Bamboo! I learn something new on this site every day!

I only take what I need from the woody herbs, for the others I am sure I remember reading of someone who chops the herbs up puts them in ice cube trays adds water and freezes. Once frozen you can put them all into a, labelled, freezer bag and just use one or two cubes as needed.

I do a similar thing with basil MG - chop it up, mix with a little olive oil (just enough to make a tight paste) and put in ice cube trays.
Also a good way to freeze garlic!

By the way Jms rosemary should not be grown in a greenhouse it needs to be out in the garden. Same is true of most herbs.