A bathroom cabinet is an excellent way of hiding much of the "clutter" that accumulates in the bathroom. Smaller cabinets can hide away shampoo, toothpaste tubes and other toiletries wile larger cabinets can handle quite a lot more - depending how large they are.
As well as varying sizes there are also different shapes, most have mirror doors some have glass doors. A lot of cabinets have built-in light fittings which will mean running a suitable electrical supply to the cabinet - this should be carried out by a qualified professional. Usually if the cabinet has a light fitting it will also have a shaver point within the unit which can also prove useful.
The majority of cabinets are designed to be mounted on a flat wall but there are some corner bathroom cabinets that take up slightly less wall space.
The popular materials for bathroom cabinets include moulded plastic, foil-wrapped MDF, wood and, less commonly, metal (usually stainless steel).
Some vanity unit manufacturers also make matching wall cabinets which is handy for unifying the overall look of your design. These are sometimes sold separately and sometimes come as a complete unit with a built in basin and a splash-back.