"Real" Chair (Steelcase / Herman Miller) and four-legged standing desk (better stability). Plus a handheld "mouse" (ELECOM Relacon) so when I'm reading I can stand differently or do light movement/exercise. Blowing $2.5K on a desk + chair is a lot, but also not a lot depending on your perspective.
My wife recently decided to buy one too, and she got hers refurbished from a company called BTOD. I was impressed with the quality. It was indistinguishable from mine (which I bought new) and cost half the price.