COMPLETED:
I built (still finishing) a vault in the corner of our basement and dry stacked concrete blocks filled with concrete and rebar.  I wished I could have a vault door installed but for now have a very thick industrial steel door with some reinforced steel refinements added for good measure.  I have a dehumidifier in the vault as well as a box fan for air circulation.  There are two concrete blocks turned on their sides on the bottom and top for ventilation as well as the gap underneath the door.  The vault is big enough that I told my wife we can use it for a storm shelter as well...so now there's plenty of supplies in there as well to last a few days.  Did I mention a big loud dog inside the house that's has other LEO in the neighborhood and the Police Chief next door?!  Location, Location...Location!

NEXT:
I need to cover the inside and outside of the block walls with Quik Wall which is a bonding cement that is troweled over the dry stacked blocks and is supposed to be much stronger than using mortar between the blocks.  I will paint the inside of basement wall that is in contact with the outside with a waterproof paint to reduce condensation on the wall.  The dehumidifier will be raised up on a couple of blocks and a hose installed so it can drain directly into the sump pump thru a block in the wall turned sideways at one block above ground level.  One wall will have either pegboard or slat wall installed for firearms to be displayed on rubber coated retail hangers.  Ceiling will be insulated and have either plywood or gypsum board attached to the rafters with sound insulation tiles installed to the ceiling.  A ceiling fan will be installed to aid in ventilation of the vault and provide additional light.  Extra phone jack will be installed in the vault for communication.  A deep cycle battery will be hooked up to a battery charger and inverter to provide some power/light if electricity goes out or is cut...attached to the inverter will be the alarm system (motion for ceiling and walls/thermal for steel door) as well as cell phone charger and other low draw AC only items.  Register vent off heat duct will be installed to allow a more uniform temperature in the vault for firearms and ME.  Storage cabinet is full of candles, flashlights, batteries, hand held CB radio, MRE's, 45 gallons of water, pertinent reading material, blankets, pillows, comfort foods, etc.)  I don't plan on getting fancy with the flooring as I'll probably just find a huge throw rug to put in there or a bunch of smaller ones.  Additional fluorescent light fixtures and outlets will be added after I decide what will go where.  Oh yeah, there will be another actual gun safe inside the vault anchored to the floor and encased in more concrete blocks filled with concrete for the bad guy to spend more time on.  The outside of the vault will be covered with shelving and other items to disguise and confuse would be burglar that doesn't know that there's anything even down there.  Along one wall will be a cheap Homak gun cabinet in plain sight for them to spend all their time on and have it filled with cheap rifles with all their internal firing pieces absent or broken, the rifles will be of the uncommon farm auction variety that you can't get parts for and haven't been made for decades.  Forgot to add that inside the vault will be book shelves with my collection of magazines (American Survival Guide, Small Arms Review, etc.), stereo, tv (as well as a small B&W DC tv) and chairs.

There are pieces of the plan that have been omitted for security sake and for others to comment on and see what they'd do to improve my setup.  Granted anyone can get into anything if they have the right equipment and plenty of time but what we're trying to avoid is the common thief and meth'd out crack head who thinks he can make a quick score to trade for some cash to buy drugs.

I was thinking of something like this.

A false back wall on a closet that could house 15 - 20 rifles across the back with a shelf on top for handguns. Wouldn't have to be very deep, just a foot or so. Thieves in house looking for crap would open the closet and see clothes hanging and maybe use it to store suitcases (easy to move for me).

I also thought about converting my mini-bar into my gun storage. It has only one entry and could easily be sealed with a serious door.

Dracster and Minuteman419 thanks for the pics as your vaults look nice.  Minuteman419 your vault looks HUGE and I'm very jealous!  I like how you've got everything spread out in its own areas as mine is a little more compact in its arrangement than that.  I'll keep any reloading equipment I acquire outside the vault as I already have a work bench built along one wall already.  I just noticed the shower in your vault and that you have your safe and file cabinet up off the floor on blocks...sump pump located in there as well?

MST2 I already have a dual battery setup hooked up to the sump pump and it's not located in the vault, sump pump well is large enough that I have a second sump pump located above the first that way it'll only come on if the bottom sump pump fails and the water starts to rise to high.  We also live on the top of a hill so our sump pump doesn't run as often as those living in bottom land or at the base of a hill.