I don't like fluorocarbon. Yes, it is less visible and I know plenty of gear fishermen who use it exclusively with no problems, but I've had it shredded by even smaller pike (never cut, though) and I remember in the days of Mason Hard Mono - I managed to get a fly cut off by a large pike. I saw it happen, and I didn't even feel a tug in my line!
So, it's wire for me. My current favourite is Knot2Kinky, which is thin and strong. Especially gear fishermen, and some flyfishers, tend to construct complex leaders with crimps, swivels, locks and what not.
I've tried many solutions, but I think my current setup is the best I've tried and used so far. It was sent to me by my friend, Niels Vestergaard. He has gotten hold of some nice snaps, and a simple knot connects the snap to the wire, and in the other end, you can simply tie a loop or even a strong leader ring, spring or a swivel if you are so inclined.
This connects easily to the 3-5 feet of heavy nylon mono, which I loop-to-loop to the flyline. It doesn't get simpler than that, i think.
I use other types of wire too, and I still like the ones you can simply tie a knot in (currently I use a brown Spro wire that works well), but I must admit that this snap seems very good. I had a couple of snags yesterday that I had trouble getting the fly out of, and the snap held perfectly, and I certainly applied more force than I ever would/could in a fight with a pike, so I'm very comfortable using them.
You can't get them through a tube, so I have to change leader when I change to a tube fly. With the loop-to-loop system that takes a minute, so I don't mind.
All in all, these snaps hold up well and aloows for a very fast and easy change of flies!
Have a great weekend!