I really think that it's important to have a good chair, one that is appropriate for a person's height and weight as well as placement against their desk or working area. I actually need one now, too. The chair I'm using was made for a shorter person with a different body type than mine, and it isn't always the most comfortable. It can only be adjusted so much.
Believe me, when you're at the computer as much as I am, it's important to have a good chair to sit in.