There are many different types of cabinet. The most popular one these days is the ATX tower cabinet. It may be a mini-tower, mid-tower or full tower.
A full list of specifications of a cabinet will be quite long. The more important ones, in simplified form, are:
1. Whether it comes with a good PSU (SMPS)
2. How many drive bays it has for hard disks and optical drives. The majority of cabinets have 2-5 hard disk-sized bays (4" wide) and 2-4 DVD-drive-sized bays (5.75" wide)
3. Whether it has front USB ports and front audio jacks. Most cabinets these days have two USB ports and two audio jacks at the front.
Other things to keep in mind:
Front-to-back dimension. Some cabinets are shorter than others and fitting the motherboard, cables and drives can be difficult.
Air flow. Good ventilation is important.
Noise. Many cabinets come with one or more fans in addition to the SMPS fan. Their noise level differ widely.