Ski poles consist of a shaft, a handle and a basket.
Length To test the length of your pole, hold it upside down and grip it beneath the basket. Your forearm should be horizontal when you stand with your knees slightly flexed.
Handle The most common is the strap type, with a loop of leather or webbing to attach the pole to your wrist. Almost all rental poles are this type. The sword-grip type consists of a moulded guard, which extends round the back of the hand. It is intended to make life easier, but in effect means that you have to trek back uphill to retrieve dropped poles after almost every fall.
Basket For skiing on piste, the size of basket is irrelevant and many skiers prefer small baskets. In powder, a larger basket prevents the pole from sinking.
Shaft This is usually made of a light metal such as aluminium, although composite materials offer an expensive, lighter and currently trendier alternative.
Straight poles are cheap and adequate for most skiers.
Corrective angles (a slight, forward bend below each handle) may help you to plant your pole correctly. A forward and a backward bend, on the other hand, cancel each other out and make little difference.
Aerodynamic poles are important for downhill racers and speed skiers. If you, on the other hand, insist on using them, it's probably pity not admiration in that ski bunny's eyes.