Haven't taken the time to set up a good BOB yet, but I do have a mid-sized survival kit I carry with me when camping/hiking.
The kit includes rubberbands, zip ties, paracord, electrical tape and duct tape for shelter supplies (virtually every type of tie/strap/band imaginable in a small bag), signal mirror, compass, hand warmers, matches, fishing kit, and water purification tablets. I store it in a heavy duty ziplock bag that I have further reinforced with a duct tape layer around the whole outside. It's watertight, so I could use it to carry up to half a gallon of water if need be.
Oddly enough, I don't have a knife in my bag.
I figure I'm always carrying one, and I typically bring along an extra bigger knife when doing any outdoorsey stuff, so it's pointless to throw another one in the bag.
Edit to add: I have a larger BOB in the works, just gotta start buying stuff... I plan on carrying 100' of paracord, a 20' roll of gorrilla tape, a dozen or so 10" zip ties, a pack of large heavy duty rubberbands (great for temporarily holding stuff while you tape/tie it down.), three MREs, signal mirror, compass, whistle, 30min road flare (no wood is too wet for one of those to light), waterproof matches, magnesium fire starter (so as not to waste matches on dry wood), a kukri, some random hunting knife, 4 liter water bladder (full), metal water bottle, water tablets, water filter to attach to my water bladder, solar charger for my phone, hand crank flashlight/radio, first aid kit, and a rubix cube to entertain myself.
