If we are going to talk about gear, this deserves a mention. These are very, very hard to find: Merkury AA NiMh batteries. There are two types, the gray and orange 2500 mAh and the White and Orange 2700 mAh. The white ones are significantly better, but the gray ones are the next best thing. Put four of these guys in your speedlite and you wont be changing it for a few hours. I usually use just two sets for a full day of wedding, though occasionally I will go to a third set. I have a speed charger that has them ready to go in 15 minutes if needed. To me this makes much more sense than spending a grand on a portable battery pack at you have to carry around on a sling all day. Oh ya, they are about $6 per set on Ebay.