I've found that for me, the biggest difference between rec, local pro, and top level pro is Mid-Range accuracy. From 100-200' they are way more dead-on accurate than other levels.
I'm not saying they don't have big arms, and don't putt lights out. But i haven't been noticeably impressed by anyone I've played with's drives or putting (unless they are just lights out one day) But the mid-range work of the better players always impresses me, and makes it obvious why they are better than me.
edit: ha, my attempt to get back on the original topic, cause i was getting tired of re-treading the same argument on baskets again and again. And i've been involved in a lot of the basket argument.