One pocket or straight pool, they seem like the hardest two games to be really good at. I'm a B player at best and have beaten excellent players in competition playing 9 ball due to a healthy spot and a lot of luck, whereas I don't believe I'd have a chance in hell at beating a high level amateur in either one pocket or straight pool - no matter how lucky I got or how big a spot they gave up. I love one pocket and don't play a ton of straight pool but I think one informs the other. I'm almost inclined to say straight pool due to the strategy and planning involved as well as the crowd management aspect. Breaking out clusters favorably, manufacturing break balls, etc. seems to require a ton of skill.