One piece of advise. Whatever goes into your go bag needs to be multiuse, and VERY robust. In a survival situation you are probably going to use this equipment harder than you would for say a weekend camping trip. If something breaks on your camping trip, it becomes an annoyance, at worst you have to pack up and go home early. In a survival situation it could mean your life. Your equipment is going to get bounced around, beat on, cussed at, and if it's not sound to begin with, get set to cry a river when it breaks. Also, look for items that can perform several different tasks. This will mean less that you need to carry.
Lastly, know how to use EVERY piece of kit that you put into your Go Bag. This includes even that odd pair of tweezers in your first aid kit. I don't disagree with having items that you may not know how to use. In a long term situation you may very well find someone who does have the required knowledge. But we are talking about a 72 hour bag here, and you cannot reasonably expect to meet the jedi master of the suture kit in that amount of time. Better to set up your go bag to YOUR knowledge, than to hope you run into the right people. Chances are you are going to want to avoid people at this point of disaster anyway.
Just my .02, I rambled a bit, but you get the idea.