Bear, Underwater Kinetics makes several nice dive knives, the one I like best is the Blue Tang. Comes with either blunt or drop point tip, partially serrated and has a line cutter. Also, it has a metal butt cap, which can be banged against your tank for signalling. Also, fully disassembles for cleaning/oiling.Runs between $50 and $60. U.K. is based, I think, out of Germany, so it shouldn't be too hard to find in Sardinia.
Ocean Master makes a really nifty one, it's made out of Beta Titanium alloy. Cosmetically it looks similar to the U.K. knife. If I were going for really hard use I might select this ($80 - $90).
Finally, Parkway makes a unique knife called the FOG cutter. It is a standard knife that can split apart to form a pair of shears. Don't know about the cost or quality of this one, but the other two have gotten good reviews from the divers I've talked to. If you run across any other good ones let me know, I'm currently interested in one myself.
Lagarto