Crankbaits are right up there with the most popular lures for bass, but they also are very popular with many other saltwater and freshwater species. They are available in every color imaginable and designed to run at a certain depth, which means working your lure in the strike zone is made easier. Every serious angler should have a selection of shallow, medium and deep running crankbaits in their tackle box.
A lot of anglers don't realize there is more to fishing crankbaits than tying one on the line, chucking it in and winding it back. Ideally you want to make sure your crankbait gets down to the bottom and "hops" over the structure, but they can also be used in free water when fish are holding at a known depth. When choosing the color don't get too obsessed and remember that action and retrieve make much more of a difference. Stick to natural colors found in the local baitfish populations and you will be fine.
Fishing crankbaits
As I am not an expert in this area so I found a couple of really good videos showing a very popular crankbait fishing technique. These are nice short little videos and are well worth watching.