Do Ergonomic Chairs Really Work?

cliffski wonders: "I've gone from a job as a commuting programmer working on his own code as a hobby, to a full time work-from-home one-man business. As I spend a good hour or two a day gaming as well as a full day's coding, I'm now sitting at the same desk for an awfully long time. Should I invest in one of those trendy ergonomic chairs that force you to sit with a straight back posture? Has anyone used one for a length of time, and does it really help prevent back pain? I've taken up archery, probably the best sport to encourage you to adopt good posture; are there any other tips Slashdot readers have for avoiding 'programmer slouch'?"