It's important, regardless of the chair, to learn to sit back and relax, and not lean forward or to one side while typing or mousing. I waited two years before buying externally-powered speakers for my Mac. I was an idiot. Even inexpensive computer speakers will improve the sound of music, games, and conversations. Again, purchase from a store where you can exchange the speakers for a different model, once you have listened to your favorite music or game on your own computer.
Intercoms are extremely versatile.
I have one here in my office, and the companion is in the kitchen. No wiring is needed. My parents in Illinois have one in their bedroom, one in the family room, and two units in my dad's basement office. It's a nuisance. Set your new kitchen timer to 25 minutes, then bounce, hop, and stretch for five minutes every half hour.