What's been really helpful in setting up your home office for FT work?

I've been FT remote for a little bit now, and have the basic gadgets I need to work (laptop, desk, chair, etc.) but I think I'll be doing the FT remote thing for at least another few years and want to invest in tools that may prove useful, but I'm not sure what I might need yet. Improved lighting? Better headphones? Just looking for ideas.