I would really like your opinions on this.
What do you think are the most important skills to develop?
If you were going to try teaching survival skills to a community group with a range of ages, what things would you want them to know about, and why?

(by the way, 5 was just a number out of the air, give as many as you want to)

It would come down to priorities, which would be, in no particular order; fire, shelter, water. Food would rarely play into it, unless you are REALLY stuck out in the middle of nowhere. Honestly, trapping and hunting with primitive weapons is largely a waste of time. Particularly if you have never hunted before. My focus, if training someone, would be:

Shelter construction (nothing fancy; a debris shelter, using natural shelters such as uprooted trees, and, something area specific ie; a snow shelter of some sort. use the KISS principle!

Fire building concentrate on HOW fire works; the pyramid (fuel, air, heat), and how to create that. Go from easy (with a match or lighter), progressing to either a fire drill or bow drill. Mind you, these can take hours to produce a fire, and can be hard on the hands & shoulders. But, if you get it going ONCE, you can at least have the confidence that you've done it.

Water procurement and purification-pretty self explanatory.

I would likely also go over useful items to have on you, in your car, and in a pack.

Lastly, getting found. Becuase,ultimately, thats what you want.

S.T.O.P.
Basic first aid, especially the ABC mantra.
Shelter construction.

After that I don't know. Fire is important, but in some situations it's impractical and a waste of energy to try.

Depends on the enviroment and what skills they have to begin with. Especially if some of the invididuals are older or already have some experience (hunting, fishing, boy scouts, whatever) you would do well to use what they know already as a foundation for more "advanced" skills.

If by survival you mean mostly staying safe and sound outdoors in a temperate woodland or similar climate I'd start with a brief discussion on the basic survival equipment (knife, PSK etc.). Show the correct way of using a knife and axe. Most people have little skill in that department but it's crucial to starting a fire or building a shelter. While you're at it, demonstrate a quick way of setting up a lean-to with a poncho or tarp. Show the best way to store and organize stuff in a backpack. Discuss the clothing and footwear most appropriate for the environment. Explain the basic navigation with map, compass, sun & moon. Where to look for water, maybe some outdoor cooking. Make it fun, it's a great way for motivating people to actually get any good at it and avoid the Rambo approach.

Only then would I go into the "hardcore" emergency survival. Eg. how to survive an outdoor emergency with only the most basic gear, light a fire in rainy weather, build a snow hole or entirely improvised shelter. IMHO the basic outdoor trekking skills should always come first and the emergency techniques should follow, not the other way around.

Also emphasize the need for getting and staying fit (you won't enjoy the outdoors nor survive an emergency if you're totally out of shape), respecting nature, observing the wildlife, learning to adapt to the natural enviroment instead of sticking out like a sore thumb. Consider organizing some extra activities such as primitive archery or tracking later on. While not directly applicable to survival in most cases they may stimulate the students to become more familiar with the outdoors and do more research on their own.

Honestly, one thing to stay away from, other than mentioning it, is first aid. If you arent qualified to teach it, dont. Tell them to get first responder qualified, or whatever, but, do NOT teach it to them. In our sue-happy society, you can find yourself in hot water.

IMHO, I'd start with building a shelter. If you're going to spend some unexpected time outside, you'll need shelter from the elements, be it cold, heat, rain, etc.
Second, I'd go for firestarting, something that isn't as easy as some think it is. If it's cold, you'll need the heat and peace of mind a fire can give. Just do it safely, we don't need to start a forest fire to keep warm.
Third - probably communication. Good communication, be it a cell phone, a personal radio or even a PLB may turn a cold night and long walk into a minor inconvenience.
Fourth - probably signaling or making yourself visible.
Fifth - can you teach common sense? Using your head and not getting into trouble in the first place.

Nicely put sir.

I think it becomes to easy to forget the things that really make life difficult to live when one becomes focused on the theoretical.

I'd say that the most important skill is prevention.

By that I mean that you need to plan ahead, let people know where you're going, when you'll be back, and what to do if you don't "check in". Dress to survive - not just arrive (borrowed from http://www.outdoorsafe.com ). Make sure you have the gear and knowledge to keep you out of a survival situation. Make safe decisions while out and about - don't take risks.

Finally, if something unexpected does happen, make sure you have brought along gear, skills, and the knowledge to get you through a few unexpected days & nights on your own (also the mantra at http://www.outdoorsafe.com ). That's the whole point of carrying a very small and portable personal survival kit - so it has the highest chance of actually being with you when that bad stuff happens - and not back at home, or at camp, or in your car.

If you can't tell, I kind of like the approach on http://www.outdoorsafe.com . To get a better feel for their approach, read their newsletter archive. There's a lot of good stuff hidden in those newsletters.

Fire water and shelter come immediately to mind.

Are you talking survival in the boonies, or in a town/community/city that has fallen to the ground for whatever reason? Long term, or short???