I consider choice of chair/laptop/monitor/headphones/etc a bare necessity, so it's good you have those ;)

If you want to make me really happy as an employee, just assume that I'll probably be leaving one day to do my own startup, and give me a helping hand along the way. Good examples might be public recognition of really good work (e.g. in company blog posts), introducing me to people, and giving me the opportunity to learn about things I'm not already an expert at.