I don't keep my BOB in my 4Runner, but it is packed and ready to go in a moment's notice. I have a SOC Gear Long Range BOB.
SOC Gear Long Range Backpack - eBags.com
I think it's more effective (and cheaper) to make your own BOB. There are plenty of forums, blogs, and websites with good suggestions, but ultimately it is up to you to decide what is best for yourself and your family considering the area you're in. When putting a BOB together for you and your family, don't forget Whiskers and Fido. I keep a week's worth of dog food in our BOB for our dog.
Putting together a BOB can be expensive, but what I did was compiled a list of what I wanted in my BOB, I pulled together things that I already had laying around the house (old hats, gloves, flashlights, knives, etc.), then I started buying things one at a time. Every time I got paid, I would buy a few things and check it off my list. You can have a BOB put together in no time without a huge, one-time expense.
I have several MRE's in my BOB but I am considering more freeze dried food to augment the MRE's. Freeze dried meal last longer and are much lighter weight if you had to carry your BOB any significant distance.
I would highly recommend a water filter. Water jugs are heavy and bulky to pack, but a water filter will go a looooong way. It's best to have both.
There are plenty of "what if" scenarios, but don't underestimate the advantages of hunkering down rather than bugging out. I think a lot of people get freaked out and think bugging out is a better option than staying at home. Unless it is a natural disaster and/or a mandatory evacuation in your area, it might be best to stay. Just something to consider.
Whether you plan on bugging out or hunkering down, you should be prepared either way. My brother and sister-in-law live in Long Beach, Long Island and just dealt with Hurricane Sandy. They said people were running out of food and water within 24 hours, and that people had started to riot in front of their town hall. Unfortunately, natural disasters bring the best and worst out of people. It's amazing to think what an otherwise law abiding citizen will do when faced with no food or clean water. The moral of the story: be prepared.