The best wireless headsets for your computers should have high sound quality and good noise-canceling in the microphone. You should also be able to get through your entire workday on one charge and get at least 200 feet away from the base. Consider getting a DECT headset for the best range, battery life, and security.
The best corded headsets for computers should be durable on both the headset and the cord. It should also be adjustable, so you can make it comfortable for you to wear all day long. You should be able to easily plug it into your computer and have it be simple to use. The first time and every time. Having a nice long warranty is also a huge benefit.
Read here about the pros and cons of both and decide which is right for you.