MIKE GEORGE says: My own preference is for a folding lock knife, with a stainless steel blade about three inches long. If you buy a quality knife you will find it quite big and strong enough for tough jobs like hide construction.
I go for just one good blade, without fancy bits like corkscrews and screwdrivers. The one I have carried for years is a Puma, but there are plenty of other good makes.
As for keeping a good edge, the secret is not to let it get blunt in the first place. A few strokes on an oilstone or one of the better proprietary knife sharpeners after every tough job will keep it keen.
I found my knife so useful I used to carry it almost everywhere I went. Now that there is an accent on the prevention of knife crime, I only carry it when I go shooting or fishing.
Carrying a lock knife when taking part in country sports is acceptable, but carrying one in the street without good reason can land you in big trouble with the law.