Well, the way I figure it is this....
In the wild, is the Ball going to have the luxury of crawling around picking out its food? Does it know that there will always be food available next week? Nah. It's more likely to pick the biggest prey it can find, and chow down before food becomes scarce. It emulates more the natural activity of the snake to feed one large prey item.
-HOWEVER-
Just because it happens in nature doesn't mean it's the best. Feeding several small prey items can ensure you don't over-feed your snake, can produce less risk of intestinal blockage, and can be digested faster. If your snake looks hungry still after feeding, you can always just pop in another pinkie to tide him/her over.

I personally feed one large item, because the stress of swallowing another item while Roo is already stuffed full with hammie/mouse/rat seems kinda superfluous. I will also occasionally shift her feeding days one or two days backwards if the last meal was particularly big, because in the wild she wouldn't have been getting feed every 7 days on the dot. I am also extremely careful about holding my snakes after they've eaten. Most people give them 2 days, while I give them 3 as a general rule. Neither of my girls are big on soaking, so after they've had a chance to digest their food I try to give them a quick warm dip in a bath to loosen any blockages up.

Like mlededee said, everyone is different, but based on what I've heard and know of animal behavior and nutrition, I prefer one larger item to several small.