Having an office, sewing, craft, reading or multi-purpose room may seem like a great idea. But if it becomes a dim dumping ground of boxes and bags with a closed door, it's a project in need of completion that likely will inspire dread.
You probably won't use a family game room if your family doesn't play games, and you won't want to spend time in a recreation room that looks like a museum. Keep it real about what works for you and what you already do, instead of what you could see yourself doing in a space.
At the same time, if there's something you really want to do but aren't doing currently, a change of pace may help it happen. But a reality check is still a good idea. A "workout room" filled with boxes still packed from the previous move, for example, may be a good indicator of how you'll use space in a new home, despite your best intentions.