Yes. If you want a 645 system. Do you like printing rectangles?
If yes, 645 is a good compromise between speed and negative size. With today's films you can go pretty big from a nice 645 negative and have enough quality, unless you're a grain peeper.
If you like to be more flexible, you should consider a 6x6. It offers the possibility of shooting square and cropping to rectangle, both horizontally and vertically. I like that.
But the cameras end up bigger, and you get fewer negatives out of a roll. Fact of life.
If you don't mind a significantly bigger camera, there's always 6x7. Less cropping, and usually these cameras are available with revolving backs, which is nice so you don't have to tilt the whole camera 90 degrees when you want to change from horizontal to vertical framing (which is a pain in the neck).
Do you need speed when you shoot? In that case you should consider 35mm. Nothing is faster, and you still can make incredible prints from the tiny negatives. Unless you're a grain peeper.
If you don't mind waiting, a 6x9 would really give you a nice negative. But you might as well go 4x5, maybe with a roll film back for more economy when shooting.
Always figure out what you want to achieve first, and what you like. Then figure out how to get there.
If it were me - Rolleiflex if I could have just one camera. But you don't like waist level finders. So the Fuji 645 or Bronica 645 would be good for you, for sure. Think about the FUJI 67 rangefinder too.