Picked up a case of WWB yesterday, I'm good to go with ammo.
Here's a list of things to bring:
guns (don't forget the sling, and you need at least 2 30-rd mags, preferably with mag clamp)
holster for your sidearm
mag carriers for spare handgun mags (pockets will work, but not the best)
water / soda / juice in a cooler
paper towels / rags
knee pads if you want them (get your minds out of the gutter)
Last year, the range was pretty wet, so bring a pair of boots or extra pair of sneakers... maybe even 2 pair if you're doing both days. I'm also bringing bags that I can put the muddy boots into when I'm done, or to put over the boots I'm wearing so I can drive without destroying the interior of my vehicle.
I'm bringing a cleaning kit so I can give my guns a light cleaning Saturday evening.
That's all I can remember at the moment. Please add anything I may have omitted.