We all carry a variety of electronic gadgets in our EDC--flashlights and cell phones being the most prevalent. Include the EDC bag and you've probably got a laptop, maybe a digital camera and other gizmos. While it may not be a matter of life-of-death if your laptop battery dies or you don't have a USB drive to transfer a large file, it can definitely be an inconvenience. This gear is essential for communication and getting our daily work done.
Here's some thoughts on support gear you may want to include in your EDC bag, to help keep your electronics up and running.
Low-tech Backups: Laptops are great for note taking, but I like to have a pencil and notepad for handwritten notes as well. Some kinds of notes are just easier to draw out or need to be quickly jotted down on the spot, and a small notebook excels at this. It also provides a backup in case your laptop craps out on you--dead battery, whatever. I like the Moleskine Cahier notebooks; they're thin, easy to carry, have removable pages, and a rear flap for holding business cards, cash, whatever. You can digitize handwritten notes into Evernote to keep them all in one, easy-to-search place.
Spare Batteries: For flashlights, phones and perhaps your laptop (though laptop batteries are heavy). Keep your gizmos running longer. I carry 8 AAs and 3 AAAs in my kit; probably overkill on the AAs, but four of them ride in a battery backup device (see below).
Battery Backup: Rechargeable backups like the Tekkeon Tekcharge are great for charging phones and devices with built-in batteries on the go. The Tekcharge has the added benefit of working as a battery charger for rechargeable AAs. I don't use mine very often, but it comes in very handy when I do need it.
Car and Wall Chargers: I like the current crop of chargers that have a USB jack, which you plug your normal USB cord into for a charge. Gives you some versatility, vs. need a different charger for each device.
Cables: I carry a mini USB cable for charging my TekCharge and connecting portable hard drives (if needed) and a short iPod cable for charging/connecting my iPhone. I plan to add a few extra cables here--CAT-5 (network cable, for troubleshooting mostly), HDMI cable for connecting my laptop to TVs.
Microfiber Cloth and Cleaner: I have a big, freebie microfiber cloth that I use basically on a daily basis to clean screens, devices and glasses. Weighs nothing, gets used all the time. The cleaner is for really dirty screens and gets used less often.
Wireless Mouse: If you use a laptop a lot, the little touchpad gets tiring quickly. I carry around a small-ish Logitech wireless mouse and use it all of the time.
Headphones: I actually carry two pairs of headphones - a good set for daily use and a cheap-o set for backup/when I forget the good ones.
Phone Headset: I'm not a blue tooth person, so I just carry a dollar store/freebie wired headset. If you need to talk on the go, while driving, etc. these are a big help.
Mini Surge Protector: If you often have concerns about the quality of a wall outlet or need to plug multiple devices/share a wall jack, these are pretty handy. Most have a couple USB slots and can double as a wall charger. The Belkin typically gets the nod.
Portable Hard drive/USB Drive: I carry an 8gb USB drive, loaded with a few useful PortableApps and some encrypted files. Mostly, I use this to transfer large files around. On trips, I will occasionally add a 1TB portable hard drive loaded with movies. If you do a lot of photography, this might be a must-have for you.
Spare Flashlight: My EDC flashlight is an untactical Fenix LD01; a bright AAA keychain light. I love it, and it's all the light that I need 90% of the time. I also have a backup light in my bag, single AA light with a clickie tailcap, which works better for tactical use. It's a $20 Rock River brand light that I picked up at Target a while back; I would like to replace it, but haven't gotten around to it yet.
Spare bulbs: If you carry an incandescent light and can't/won't switch over to LED, it'd be wise to carry a spare replacement bulb.
Mobile Wi-Fi Hotspot: There are several of these on the market, the Sprint MiFi being the best known. They connect into cell networks and let you set up a portable wi-fi network. Contracts and monthly fees make this an expensive option, but if you've got to stay connected...
EDITED TO ADD: Having a portable copy of Linux (Damn Small Linux is a measly 50mb) is very useful if Windows gets corrupted and you need to get into your machine and access/back up your files. Also, BACK UP your data and keep a boot disc and your machine's drivers close by.
What did I miss out on? Any other support gear to consider? What do you carry? Comment.