I don't know a lot about the equipment out there, but the one thing I'd vote for is the extra battery. No matter what kind of digital I've used, I've always had at least one spare (a set of AAs for the point and shoots, specialized for the Nikon, doesn't matter, as long as they're rechargeable). It's cheap insurance against finding out the remaining charge wasn't as much as you thought, it's cold and the battery drained faster, there were so many interesting things to shoot you used it up, whatever. Without a charged battery you've got a funny shaped paper weight. I've also had the habit of, whenever I swap batteries, photographing the one I just took out. That way I'm reminded to recharge it. Just my 2 cents, whatever that's worth these days.