The Guitar Pick
Picks, or plectrums, come in a wide variety of types and shapes, each of which can be made of a variety of materials such as brass, steel or plastic, and of varying thickness, to control the flexibility of the pick - thinner picks are good for strumming, thicker ones generally for picking individual strings. Classical guitarists primarily use their fingernails, which must be carefully maintained at the proper length (sometimes using super glue for added reinforcement!), or some use fingernail extensions, which fit over the finger but have the picking edge underneath the fingernail, to retain the feel of the player's nails.
Acoustic guitarists, especially in country and bluegrass, often use metal or plastic thumb picks and finger picks. This approach takes a little getting used to, but offers a sharper, brighter attack than is possible with just the bare finger. Some players favor hybrid picking, which involves the use of a flat or thumb pick and the free fingers. Most rock and blues guitarists use some type of the familiar flatpick. The Fender 351 shape, like a rounded isosceles triangle with one point, is probably the most common shape. The Fender 355 pick is shaped like a large equilateral triangle, and has the largest body of any pick that Fender makes, so you've got plenty to hold on to, and three picking points, so you can just spin it to a fresh point when the one you're using starts to get worn too dull. Many jazz guitar and mandolin players prefer the smaller teardrop guitar picks, like the Fender 358. These can be a bit more tricky to keep hold of, but can offer greater agility and responsiveness between the fingers. Read More>
Regarding the material used, players have been shaping plectrums (or plectra, if you want to be formal about it) out of wood, bone, amber, stone, ivory, glass, felt, metal and anything else they could find for probably as long as there have been stringed instruments. Tortoise shell was widely used for everything from guitar picks to pocket combs, until its use was outlawed in 1973. Today, plastic is by far the most common material, though there are several types of plastic, most notably Tortex, nylon and celluloid, though some players use old credit cards or filed bits of broken CDs in a pinch. You can even find picks made from meteorites at auction sites, if you have a few hundred extra dollars!
You might want to investigate what your favorite guitarist uses - Jimmy Page and David Gilmour have both been known to use Herco Flex 75s, Stevie Ray Vaughn played Fender medium picks, using the round end, and Brian May of Queen uses an English sixpence coin, which is about the size of a dime and has a serrated edge. Similarly, Billy Gibbons of ZZ Top uses a Mexican peso. Most major-league players these days have their own custom-printed picks, which they throw out to the audience during their shows. This has spawned a cottage industry of pick collectors on eBay and other sites, where music fans buy and swap vintage picks used by their idols. You can even order a set of custom picks yourself from several makers such as Clayton at nominal cost. And there are always new variations on the venerable pick hitting the market, some more of a gimmick than others, but all with their own charm. For instance, novel designs like the Jellifish plectrum or the Dunlop Strummer use multiple tines set at a beveled edge, so they make contact with the strings in succession, and can offer a 12-string or chorus effect when used properly. The E-Bow is like an electronic bow for your electric guitar, used in place of a pick, which generates almost endless sustain and other effects, and can be heard on tunes by Radiohead, U2 and R.E.M., among others. The original Pick of Destiny, sadly, is no longer available, but you can even get a functional replica of that! The best way to decide what is right for you, however, is to get a little knowledge, check out the offerings from Dunlop
and some of the smaller manufacturers, and then experiment. Now get picking!