Debian linux tips:
I do not rely on graphics mode (X window) when configuring linux, and none of these configuration tips requires graphics. So they remain helpful even if graphics driver fails, or if you have to maintain remote linux system. Except for the wifi-switcher, all software used here is available from the standard debian linux repositories.
Good and compatible hardware: Asus, IBM/Lenovo Thinkpads.
HP printers/all-in-ones: good if someone else pays for ink and toner. HP has good linux-compatibility, but it does its best in preventing people to save on ink and toner. E.g., on HP Officejet 6700 Premium it is impossible to print even black and white text if yellow cartridge is empty. And you can not manually refill the cartridge for a few bucks, because a HP installs a chip on its cartriges that makes them unusable once they are emptied for the first time. It is possible to buy cheaper "generic" cartridges which pretend to be original HP ones, but I just do not want to play these games; so I avoid buying HP.
Bad or incompatible hardware: Acer, Lenovo IdeaPad, Xerox.