My BOB is a Piper Gear Three Day Pass backpack in black. It's relatively inexpensive (around $50) but good quality.
Here's what I have in my BOB so far, in no particular order:
- 3 rolls electricians tape
- 1 roll Gorilla Tape
- extra pocket sized tube of Vaseline for lips
- Lansky turnbox knife sharpener
- Stanley pocket box cutter
- pair of SUG work gloves
- 2AA Maglite flashlight with LED and clicky tailcap upgrade
- 2AA Maglite flashlight with extra bulb in tailcap
- 3AA LED Maglite flashlight
- surefire G2 flashlight
- extra P60 bulb for Surefire G2
* You can never have too much available light
- a bunch of extra Duracell 2AA and Surefire CR123 batteries for flashlights
- Torx driver with 8 different sized bits
- Allen driver with 7 different sized bits
- Buck 110 folding knife with belt sheath
- Gerber Parabellum folding knife (original version with 440C steel and multi-carry sheath)
- length of 550 paracord
- roll of toilet paper
- Cold Steel ODA fixed blade (Carbon V version) in leather KaBar sheath
- original ODA sheath
- Mexican machete with 16 inch blade and leather sheath (I'm more experienced with a machete than a hatchet, and it works pretty well as a chopper, even on hardwood)
- Bucket Boss Annihilator demolition hammer strapped to outside of pack
The next thing I'm going to add are some fire starting materials.
I carry some things that I haven't mentioned on my belt every day, and I keep a medical bag separate, so I've got those covered.
Edit: I'm getting some good ideas from this thread about stuff to add.