I still use a $35 leather office chair I bought at Target. No back strain for my 6-10hr sessions, it has arm rests, it can lean pretty far back, it has wheels, and adjustable height. If you're paying for anything more, you're paying for vanity. I've tested some of the high-end gaming chairs - the ones with speakers, subs, controllers, fridges, etc. built into them - but in the end, they aren't anymore comfortable than a standard nice office chair. In most cases, they are more uncomfortable because some of them are designed purely for show and not for extended sitting, whereas office chairs are specifically designed for ergonomics.
Edit: Just checked out the Herman Miller Aeron chairs and those are the extremely fancy office chairs. Those are ridiculously comfortable, but I highly suggest only grabbing one of those if you have plenty of disposable income.