My top 3 ( and next 3) vary by circumstance. For daily life, going to work in an office or hanging around the house here is what tends to be with me.

1) knife - usually a swiss army money clip with some $ in it
2) small flashlight - single AA LED (peak solutions)
3) cellphone/iphone

4) wallet
5) keyring - just keys
6) small "jet" Lighter

The reason the above are always with me is I use them several times a day (well except the lighter but it just seems like a smart move to have an easy source of fire around and it does get used about once a month).

Of course if you ask my wife or my coworkers they would tell you it would be very rare for me to be caught with this little on or around my person but this tends to be what is always (or nearly so) in my pockets.

I used to carry a more capable knife and multi tool but they didn't "fit in" well in my office environment so they have been relegated to a small hard drive storage case I keep in my office / computer bag.

- Eric

Ok, anyway I believe 3 is not enough. But my choice would be:
1) multitool;
2) Bic lighter (better than a torch for light, and for high altitude/wet conditions firemaking);
3) Smartphone. In addition some modern smartphones have a very bright screens, which often works much better than your average single AAA flashlight, and some have UB LED flash for the camera, which could be programmed to go off continuously. Advanced models may have standalone FM Radio module built in and a regular GPS unit/compass. Throw in a plastic belt holster (or resin skin) and you've got plenty of tinder too

Seriously, the number of items means nothing. The weight and volume does. What can prevent me from stowing a couple of scalpel blades behind the phone's battery door for example? Limit of 3 items per household?

Water procurement

Fire

Knife

Recent humiliaton has led me to add a caveat to my list:
Trying out a sleeping bag in what's probably the last really cold night this winter, i had to erect a tent in the dark
as an aside; the bag kept me toasty warm in -4 so UK peoplel get down the army surplus and buy those cheap ex-army down bags on sale. waterproof base, rainproof when rolled up and the carrying handle and 2 toggles give you points to secure it on the outside of your rucsack.

Erecting a tent in the dark; moi? no problem! i've had that tent decades and put it up hundreds of times.
1 it wasn't easy; a few years of not putting it up and i'd forgot a lot.
2 oh how quickly i realised doug was right to reject out of hand any lights you have to keep a button depressed to work. primary light; completely useless.
3 no problem' i'm mr "and if i could only carry 2 items both would be torches" the second lights battery was almost dead. faded in 20 seconds
4 ah but ETS man has backups for the backups. spare battery in belt is; err... missing.
" do you have a torch dear?"

so however many items you carry; they also have to work and you need to have practiced using it.
The Sock

1. Multitool
2. Flashlight
3. Fire Starter

For those are generally a skeletool, Surefire E1B, and some kind of lighter.

What the ideal type of each is could be (probably will be) debated to no end.

Fact of the matter if these aren't generally carried for "survival" in the sense we all think of, they're carried for actual survival on a day to day basis making my life easier. Today I used the multitool and lighter, most days I use the flashlight. Just nice things to have with me. That said, if I somehow ended up outside some night, I could probably get a fire going to keep warm by while I was thinking about whatever stupid action left me on an unplanned night out.

Wow! I lost my login and password to this forum for a few days and look at what happened? :-)
Thanks for all your posts. I've enjoyed reading them.
For me, again it really all depends on what you're doing and where you're going. For example all of you that answered knife, gun, etc... what if you're in an airport catching a plane it a few minutes? Your stuff would change no? (Unless you go and enter one of the many restaurants that provide knives after you've been cleared by 'security' and put one in your pocket again).

I also like to think of it in terms of essentials. If we don't have clean air to breathe we're in trouble. That's where my ounce and a half, pocket-sized, Breath of Life Emergency Escape Mask, comes handy (according to FEMA every 2hrs an American dies in a fire and 75% die from inhalation of smoke and toxic fumes).
So, having that cleared... what can be the next worse thing that could happen to me? Probably not be able to stop bleeding (most common cause of death in trauma scenarios).. that's where my RESQPAK comes handy.
And for me... the 120 lumen flashlight just 'lives' in my pocket so this could be handy for blinding someone (including in an airplane), controling panic (including in a subway) and for finding my damn wallet every time I drop it under my car seat :-)

Keep 'em coming!

So what about the training (or lack of) that we carry with us and hopefully enrich constantly? Wait... that's probably a good enough 'theme' for my second post!

since a cell phone is not part of the three, i'll make mine
Multitool
Light
Lighter

this is EDC, not survival oriented. if we're talking survival gear then a three item limit seems a bit silly, but i guess i'd go with the B*** G***** set up of fixed-blade knife, steel canteen cup, and firesteel. with a basic knowledge base, that covers the three essentials of fire(which by proxy also covers illumination and signaling), water, and shelter.

Over the years, I've really settled my EDC into a small, but useful kit.

The three things I ALWAYS carry are:

Multi Tool
Bandanna
Key Ring with Flashlight (Pico), Whistle (Fox) and Tiny Pen Knife (Swiss Army). Ok, that's technically three items right there, but it's ONE keyring, so I count it as one item.

Also, I'm going to be repacking my 100% non-hypothetical kit again, a kit that I developed as a fire/rescue guy and it was/is a kit that had a lot of stuff in it that I actually used in actual emergencies. There's a few surprises in there.

Things I alway have on me when I go out (not counting wallet):
1) Benchmade Griptilian 551, one of the most sturdy folders I've ever used.
2) Doug Ritter's Pico Lite on my keychain. Very bright and SUPER tiny!
3) Cellphone (Blackberry) is a must!

By the way ... for those concerned with survival: according to the formost experts today the order of the things you have to take care of is as follows:

1. SHELTER.
2. WATER.
3. ...and only then FOOD.

Now, regarding the items that I carry on a daily basis in my city routine (now that I discovered how to put a link here), I get them at http://ProactiveAndPrepared.com

Hope this helps.