What do you successfully use to map out an existing 'Nix server?

We're looking for something to build a beautiful report of all the hardware, installed software, running services, repos, users, privileges. Everything on a linux server!

Sometimes we take over IT for a small(-ish) company which have no documentation and need something to discover the system for us.

Bonus points if your suggestion can do Windows at the same time!

Thanks for your feedback in advance!