If you're past the point of wondering how you're going to buy your next meal and make rent, then yes, it is absolutely worth it.

I use a Steelcase Leap (I tried the Aeron, but prefer the Leap, go sit in a bunch and see what you like) and it's been worth every penny compared to the Office Depot chair I has previously. I don't sit in it and think "wow, this is a comfortable chair" -- that's not the point. It just becomes an extension of your body and you forget it's there at all. I can sit in it for hours without becoming tired or uncomfortable.