If your company will spring for one, that is. But take a 15-minute break every two hours. This doesn't mean you have to stop working entirely, though you'd probably like that. Just move around and do something completely different. Run to the copy machine, grab a glass of water, or return a phone call while standing on your head.
Individual comfort tempered by individual preference is the key to ergonomic correctness.
At the very least, get up and get moving and you will be more fit, less bored, and less prone to ergonomic injuries. You have a lot of years of computing left, so plan on keeping them pain-free.