Most streamers that you'll see are tied on a standard hook with a straight shank.
These hooks get the job done well and can be easily found at any fly shop. However, like many things in life, improvements can be made. Aside from sprucing up or modifying an existing fly pattern's materials, changing the hook style itself can make a difference for the better. That's where the jig hook comes into play!
The jig hook's difference in design over a standard hook is pretty obvious. The end of the shank and eye bend upwards (commonly at about a 60-degree angle) which provides several advantages for weighted flies meant to ride hook-up.
Tracking- Since the eye is on the same side as the hook point, weighted flies tied properly on a jig hook tend to track more upright. One common trait with a standard hook is that some flies may roll over more easily when stripped or pulled. With a jig hook, the eye positioning and slight resistance from the leader on the eye helps keep the hook point up where it should be.
Fishing Around Structure/Cover- A jig hook won't make your fly totally weedless, but it does help. With a jig hook that has, say, a 60-degree bend, that bend acts like a little ramp that allows the fly to deflect or slide over objects better and protects the hook point. This also makes these hooks great choices for bottom-thumping flies that are often fished around rocks, etc.
Hooksets- On a normal hook, the eye sits at a much lower level than the hook point. Because of this, when setting the hook the pulling force on the hook isn't totally straight. On a jig hook, the eye sits up higher and is closer to being inline with the hook point. When force is applied, the hook is pulled on a straighter path which leads to a cleaner hook set.
Likely the most popular fly to use with a jig hook is the Clouser Minnow. Since it is weighted with dumbbell eyes on the top of the shank and can be fished from just subsurface on down to the bottom, this fly is tailor-made for a jig hook. But, it doesn't stop there—any weighted fly meant to ride hook-up should be able to benefit from a jig hook. Even bead-head nymphs are being tied on tiny versions of these hooks. Try em out!