While I realize no financial gain from doing so, i will shamelessly plug Doug Ritter's Pocket Survival Kit as a fantastic starting point. I think it lacks a light, but that is a personal choice and easily remedied. There is still room inside the pouch for you to add a few things. The sparklite will ignite the included tinder. I carry other methods in my more extensive kit but the pocket kit goes everywhere I do. A great starting point, when also carrying a good knife

My EDC (belt) on the boat:

Buck 110
Leatherman
Mini Maglight w/spare bulb
Ferrocium Rod w/striker (thank you, Stu)
2-4 AA batteries
Bic lighter
Soap stone

My EDC (clothing) on the boat:

Pocket Watch
Bic ink pen
Bic lighter
cell phone
Eyeglasses w/case
Wallet w/ID & cash
Pocket calendar
Bandanna
Comb

My EDC (life jacket) on the boat:

55 gal garbage bag in a ziplock
2-35gal garbage bags in a ziplock
whistle
signal mirror
Red Blinking Marker light
8" Crescent wrench
Plastic hardhat

My GHB is stowed in my stateroom

Some items to perhaps consider for a PSK kit.

BCB Mini Mess Box
http://www.bcbsurvivalusa.com/xcart/catalog/BCB-Mini-Mess-Box-p-16156.html

Caselogic Small Hard Drive Case, EVA Outer, Black
http://www.amazon.co.uk/Caselogic-Small-Drive-Case-Outer/dp/tech-data/B000HDJT4S/ref=de_a_smtd

BCB wire saw.
http://www.bestglide.com/Wire_Saw_Info.html

Compass - Silva Escape & Evasion Compass 40 Luminous
http://www.springfields.co.uk/bush-craft-field-kit/location-aids/compasses-whistles/?id=3148

10 Lifeboat NATO matches plus striker NSN 9920 99 737 1041
http://www.brigadeqm.com/cgi-bin/tame.exe/store/level4c.tam?M5COPY.ctx=31398

Pak-Lite SUPER Glow White LED Flashlight + Ultralife Lithium 9V Cell
http://www.9voltlight.com/inc/sdetail/14555

Fenix LOD AAA cell flashlight
http://www.amazon.com/Fenix-L0D-Level-Performance-Flashlight/dp/B001GAOO9G

Small Boker Subcom copy knife or even the genuine article or space permitting a SAK Forrester
http://www.dealextreme.com/details.dx/sku.19364
http://www.knifecenter.com/kc_new/store_detail.html?s=BO589
http://www.amazon.com/Victorinox-Swiss-Army-Forester-Multitool/dp/B0007QCOTW

Butane Lighter (compact, durable and reliable)
http://www.dealextreme.com/details.dx/sku.16699

Small tube of Vulcanising Rubber Solution (available in commercial bicycle repair kits) such as;
http://www.simpsoncycles.co.uk/product.php?xProd=1898

20-25 metres of Kevlar Tying Thread rapped around a selection of needles (doubles up as a make shift fishing line with some small hooks, snaps swivels and a single small weight etc)
http://www.amazon.com/Kevlar-Thread-Colo...=nosim/kkorg-20

Titanium Whistle (very small)
http://www.uniquetitanium.com/titanium_whistles.htm

Esbit Hexamine 3 x 14gram Solid Fuel Tabs (If container size allows)
http://www.rei.com/product/653344

Titanium Wing Stove
http://www.backpackinglight.com/cgi-bin/backpackinglight/titanium-esbit-wing-stove.html

Small Candle (beeswax impregnated with Citronella) cut down to fit PSK container
http://www.bearcreekcandlecompany.com/becica1.html

Bog Myrtle (natural insect repellent) or even a small block of Bog Myrtle Soap.
http://www.amphora-retail.com/myrtle-essential-10ml-p-237.html
http://www.highlandsoaps.com/cat-9-subcat-17-product-403

ALOKSAK Element Proof Bags (various sizes etc for carrying water, waterproofing gear etc)
http://www.bestglide.com/aloksak_info.html

Alcohol Prep Pads (cleaning wounds and fire lighting)
http://thefactorydepot.com/Acme-United-5...ce=GB&id=uk

Ultimate Survival Starflash Signaling Mirror
http://www.basegear.com/starflash.html

1/3 of a Bahco Bi Metal hack Saw Blade
http://www.amazon.co.uk/Bahco-3906-300-3P-Hacksaw-Blades-12In/dp/B0001IX7YW

Swedish firesteel mini (dump the striker and use the Bahco blade instead)
http://www.rei.com/product/762946

Water Purification and Neutralising Tablets
http://www.justincasesurvival.com/kamiwaputa.html
http://www.gear-zone.co.uk/eshop/Lifesystems-Neutralising-Tablets.html

Small Medical Kit

Codeine Phosphate, Ibuprofen, Aspirin, Imodium, Piriton, Tetracycline (full Course)

Potassium Permanganate.

Surgical Blades, Butterfly sutures, Plasters, 3/8s suture needle etc.

A few sheets of A6 Waterproof paper (write in rain) and a Fisher Space Pen refill wrapped in duct tape

http://www.rvops.co.uk/field-kit-81/waterproof-notepads-70/all-weather-notebook-935t-1723.html

http://www.spacepen.com/refills.aspx

Heatsheets BIVVY SACK Emergency Survival by AMK (space permitting)
http://www.redflarekits.com/pc/1038/rr/Heatsheets+BIVVY+SACK+Emergency+Survival+by+AMK

Mosquito Head Net (again space permitting)
http://www.lifesystems.co.uk/psec/mosquito_nets/mosquito_headnet.htm

How small do you want to go?

Smallest is my key chain (hotspark, micra, whistle, pill case w/ cotton ball, advil, immodium and benydryl), pocket knife, Vic Climber (which has a Fenix EO1 on it).

Next step is my PSK. That is part of my EDC, which adds cordage, lights, batteries, knives, tools, emergency poncho, contractor bag, nalgene, cup, compass, maps, gloves...

And that is what I carry when I'm in my town. *blush*

I carry, in my pockets, a match safe with w/p-w/p's and some commercial tinder, two minibics, a three-inch folder, an old LM wave, ten or twelve feet of paracord and a Steamlight 2-cr123 TwinTask, whenever I'm out in the woods. And even when I'm not.

Also, for the woods, I have a belt pouch kit, that usually resides in a lumbar pack, that has, among other things, two large trash bags, a heetsheet blanket, a small FAK, more paracord, a photon, water treatment tabs, a roasting bag for water and a smaller folder (Spydie Dragonfly). It also has most of the contents of the Ritterkit. There's a Sierra cup dangling from a biner attached to the pouch. I usually wear the lumbar pack when I don't have a backpack, so I can carry water bottles. If not, I put the kit on my belt.

I sometimes wear a sheath knife, which carries another small flashlight, a firesteel, tinder and some bug spray. With an emergency poncho in my pocket, which I almost always remember, I think I would be fine with my pocket carry alone, most of the time. The sheath knife helps, and with the belt pouch, I'm livin' the life of luxury.

The simplest, cheapest and best way to begin to assemble a kit is, IMO, to buy a Ritter PSK. Add a knife, a fire kit, and an AMK heetsheet, maybe a poncho and you should get through a lot of trouble. The Ritterkit isn't everything you need, but there's nothing you can't use, and the quality is unmatched for the price.

Re the knife: If it's a pocket kit a locking one handed SAK like the Trailmaster is strongly recommended. Decent blade and a superb saw.
Add at least 20' cord, a waterbottle and a metal cup.

Yeah, what I do is to carry the Wave - mostly for the saw, which I seem to use a lot. I keep paracord in my pocket, because I no longer use the original pouch that the Ritter Kit came in. I use two steel water bottles and a sierra cup is always hanging somewhere - from the belt pouch or my belt, or it's in the lumbar pack.

The Trailmaster sounds like a more efficient way to have a knife and saw, but I always have both the folder and the Wave on me, anyway, because I use the Wave at work a lot. If I had a new Wave, with the better blades, I might not carry the knife at all as EDC.

My PSK is built around the Pocket Survival Pak which in my oppinion is a great kit.

I have added...
Disposable Sunglasses
Opinel Folding Knife size 7 i think
12 hour red cyalume
Pak-Lite
Foil Blanket
Katadyn Micropur MP-1 tabs
Length of bicycle inner tube
Swann Morton scalpol handle and 1 pack of no10 blades
10 meters of cord
Lifeboat matches
small fire steel
Glass signal mirror
Surefire torch
Laser Flair
4 spear 123 batteries

This all fits in a small pouch i wear on my belt when out and about or throw in my daysack as and EDC.

In order of use -

Light/multitool (just about a tie for me)
FAK
Water
Poncho
Repair kit

I'd always add a whistle and a lighter, but I've never had to start a fire in a crisis. You are far more likely to need a screwdriver or a band aid than a fishing kit, and you might plan accordingly

I'm not sure anyone really thinks they're ever going to use that fishing kit. But I carry it, anyway.