Summary:
Perhaps the most important piece of fly fishing gear you will need to choose is your fly fishing rod. Though fly fishing is a simple art, it is a precise one. When reading the riseform on a river trout, you will need a rod which you can depend on to cast a precise cast - not wide of your intended area, nor falling short. You will also need to know that when you get in deep to the mountain streams, your fly fishing gear will not fail you and break down at that critical moment.
Perhaps the most important piece of fly fishing gear you will need to choose is your fly fishing rod. Though fly fishing is a simple art, it is a precise one. When reading the riseform on a river trout, you will need a rod which you can depend on to cast a precise cast - not wide of your intended area, nor falling short. You will also need to know that when you get in deep to the mountain streams, your fly fishing gear will not fail you and break down at that critical moment.
If fly fishing is itself simple in practice (though not easy!), the world of fly fishing rods is not. Gone are the bamboo rods of your forebears. The technology in fly fishing rod engineering has exploded, and there are a plethora of choices to choose from.
Most rods today are made from graphite. Basically, you want a rod that will precisely cast, that controls your line once cast, and lands your fish - often, when the fish are lionhearted fighters, in tough water conditions. Given that, how to choose?
What are you fishing?
Top on the list is to know what type of fish you are looking for. A largemouth bass behaves differently in its pursuit of baitfish than does a brown trout. It also fights differently. What will hold up for a small brooky will not do well for a lunker on the line.
What water are you fishing?
Second, the water you fish will tell you a lot about the type of rod action you should be looking for. If you fish mostly smaller streams, and are in need of precise, gentler, shorter casts, you will want what's known as a full flex rod. This type of action will also allow you to have a better feel for the fish on your line. As with walleye fishing with spinning reels, a light, sensitive feel will often better land the fish you seek.
On larger streams, or if you don't want (or you're budget won't allow you) to have several different rods for different purposes, a mid-flex rod will provide adequate strength to fight tougher fish, or fish landed on tougher conditions. Because it is not a fast action or stiff rod, you will still have some sensitivity on the line, but you can cast farther and more precisely than with a full flex rod. This is the most popular type of fly fishing rod out there.
Finally, under heavier wind, on tougher waters, on bigger rivers (or ocean fishing areas), or with tougher, bigger fish, the "fast action" or stiffer rod is the way to go.