This seems to be the nearly universal original 10 Essentials list:
2. Compass (optionally supplemented with a GPS receiver)
3. Sunglasses and sunscreen
4. Extra food and water
5. Extra clothes
7. First aid kit
8. Fire starter
1. Map, good to have, but that could be anything from Mapquest/Google directions to an actual map. Times have changed. In a bug out situation, you want to get from point A to B. Basically, you need to know where you're at and where you're going. When camping/hiking, you want to have an actual USGS approved topo map of the area. Reason for this is...
2. Compasses are great tools. But you have to know how to use them. GPS is probably the greatest user-friendly navigation tool known to man. It's also accurate. Geo-caching is based around it and is a lot of fun. But, GPS can go down and does go down depending on your location. Learning to use a compass is important.
3. Sunglasses and sunscreen. Important in a desert climate, but what the core of this is about is not exposing yourself to the elements. That's going to depend on your area and location. For me, I'd substitute Rain Gear or waterproofing if necessary. I carry sunglasses, but also a foldeable waterproof poncho, but that's where I'm at. Basically I'd call this one "protection from inclement weather."
4. Extra food and water. - Extremely important. I really like Mountain House stuff. To me, it tastes better than MRE's, holds just as long, is extremely light and works great in a BOB.
5. Extra clothes. Also extremely important. 2 pairs of everything. 2 is 1, 1 is none.
6. Headlamp/Flashlight. - This used to be "flashlight, extra batteries and bulb" - Remember that one, not the other. Carry extra batteries and a spare bulb for your rig. The batteries WILL run out at some time. Kind of bothers me they don't teach that in the new stuff. - Extra set of batteries and an extra bulb if you break it.
7. FAK. Definitely. Or make your own. Most of the people I've talked to have said to include more bandages than band-aids. If you're in trouble, a boo-boo isn't going to kill you, but you want something to save a life and stop bleeding. I'd reccomend some of ZS's FAK threads, there are some darned good ones on here. Serious.
8. Fire starter. Waterproof matches suck. Get a cheap bic or zippo. And yes, that dryer lint stuff is true. BTW, as someone who lives in a wet climate, carry candles. Not only are they a back up fire starter, they will work to keep you warm and get a campfire going even in the worst situations.
9. See above.
10. Knife. I carry a Ka-Bar, but I prefer to carry a hatchet. It's much better for moving trees and getting kindling.
My humble two cents. Hope that helps.