These keyboards are the most widely available and can be found in your average computer supply shop. The inexpensive ones will often have noisy keys and will not be especially soft to the touch, whereas the more expensive types will have a membrane covering to combat such disadvantages.
If you do not have any serious special needs to consider when choosing your ideal keyboard, then consider the following:
Wireless Keyboards
Continuing the growing trend of getting rid of unsightly and messy wires, wireless keyboards are a great option and well worth considering. They utilise either infrared or radio frequency technologies and will cost slightly more then a standard wired keyboard. They can also be standard shaped or shaped to fit onto a small area of your desk (e.g. wave-shaped). Of course, specialised wireless keyboards are also available.
Ergonomic Keyboards
Designed for people who may have wrist or arm injuries, these keyboards are often sold as adjustable split or fixed split. Both are split in the middle and use an ergonomic angle to maximise comfort. The adjustable version can be angled or modified as desired, while the fixed versions are more limited albeit easier to operate.
USB Keyboards
Most personal computers provide these ports, although check to see if you have any spare as they are often used for a range of other peripherals, such as printers or modems.
Should you have already bought a USB Keyboard and have run out of ports, you could consider investing in a USB hub as a solution to this problem. Again, many of the various types of keyboards explored here will have USB as an option.
Touchpad Keyboards
These allow the user to access the mouse cursor without having to remove their hands from the keyboard. Again, these are ideal for people with wrist injuries.