With 4 gigs of music, I initially loaded my iPod up with an eclectic mix of songs and went for diversity figuring the cost of overage (too many songs/variety) was less than the cost of underage (not enough songs/variety). However, I’ve found I generally just put it on Shuffle mode in order to maximize battery life. I recently deleted a bunch of marginal songs from my iPod and my satisfaction with it has skyrocketed.
It occured to me that there is applicable to the business world as well. Firing your marginal customers (or employees!) will probably make your life a great deal easier, more profitable, and enjoyable. In some cases, less is more.