I've posted pictures of most of my personal EDC gear recently, but I will say my gear is by no means "the best," what everyone should carry or even what I would carry given more funds. I'm working towards improving my EDC gear towards something like the below.
I'm also personally somewhat picky about how much gear I carry around, so my "ideal" EDC reflects that. Some people don't mind carrying more and others can't stand carrying much of anything in their pockets. Your EDC is a personal thing and will need to be tailored to your personal tastes and lifestyle. Also, this is an everyday carry, not your wilderness/camping, etc. carry.
Must Haves
- Knife: A quality folding knife for utility purposes and last-ditch self defense. 3" to 4" inch blade, one hand opening and a good lock mechanism. I like Spydercos, but there are a bunch of good knives out there to choose from. A good multi tool with locking blades or a small fixed blade like the ESEE Izula may be alternatives.
- Wallet: This is a given (I hope), but make sure that you keep some spare emergency cash hidden away inside. You can also fit a small bit of duct tape wrapped around a card, a couple bandaids, a safety pin or two, etc. inside your wallet without adding much of any bulk.
- Keys: Also a given, and also a decent place to add a few small tools. Keychain light and a mini-multitool.
- Flashlight: I consider some kind of light a must-have, but it doesn't have to be massive and all-powerful. With today's LED tech, you can fit a pretty powerful light on your keychain; a Quark MiNi, Preon or several of the Fenix AAA lights are good options. Mainly just for navigating safely through the dark, finding keys at night or looking in dark places.
- Concealed Carry Handgun (if you carry): Something that is compact, comfortable to carry and reasonably capable will do the trick for most. I think guns like the Smith J-Frames, Glock 26, the compact M&P and similar are good choices for this role. If you can't or don't carry a concealed handgun for whatever reason, I would carry a knife dedicated to self defense (a waved folder or a small fixed blade).
- Cell phone: Ideally an iPhone or similar smart phone. There's so much crammed into these nowadays. I'm currently getting by with a $20 POS phone, so you can certainly live without a fancy phone if you're so inclined.
- Pen, pencil or Sharpie: Yep, for writing! And don't bother with those ridiculous "tactical self defense special ops delta force-approved" combat pens. Save your money. If you're worried about needing to shove a pen into someone's eye, you can get a stainless steel Parker Jotter for like $7.
- Sunglasses: If you live somewhere bright and sunny; make sure they're actually quality enough to protect your eyes from flying debris/shell casings, etc.
- Bandanna/hand kerchief: Infinite uses.
- A way to start fire: I'm "meh" on this; can probably be relegated to your bag and vehicle kits unless you're camping, hiking, etc. A small ferro rod on your key chain is pretty easy to carry, though.
- Watch: Lots of people get by without one or by using their cell phone, but I like to have an actual watch on my wrist.
- Meds: If you're on any important medications, I'd carry a backup supply on-person. I'll throw chapstick in here, too. If you need it frequently, you'll probably want to have some with you.
- A USB drive or memory card: If you need to move large files between multiple computers or run portable apps, though with cloud storage and large file relay sites, these are becoming less important.
- Cordage: In the form of a paracord bracelet or fob. You probably won't ever need the cordage, but it's pretty easy to carry around, especially as a keychain fobs.