Gaming PC - Always. I continuously upgrade as needed. Currently high end.
Nintendo: I own a switch and will own whatever its successor is. Very helpful now that I'm a dad and can't monopolize the TV.
Sony: I will very likely buy the PS5. They have a proven track record with first party titles and exclusives. Full backwards compatibility would greatly increase the chances I will purchase.
Microsoft: It's possible I might buy the next XBOX. Still weary on their first party lineup, especially since much of it will make its way to PC. Full backwards compatibility would greatly increase the chances I will purchase. Being the more powerful system of the two would also increase chances I would buy.