Stills come in many designs. The most common stills are traditionaly made of copper, though in recent years stainless steel has made inroads in the industry. Almost all stills employ some sort of copper because it removes sulphates on contact.
A very detailed page on column still design is How to build a Boka Still.
There are two common designs of stills. The first and most common is the pot still which is used to produce whisky, brandy and other spirits which rely on flavor from the mash. Pot stills consist of a boiler, a condenser, and a lyne arm through which vapor travels from the boiler to the condenser. The lyne arm has a bend in it known as the lyne angle. Some pot stills have a thumper which serves to further purify the distillate. A heat diffuser can be used to prevent scorching inside the boiler
See also rectifier.