Store it in my gun safe. Ill clean it and every once in awhile make sure it still functions then clean it again. Haha.... I would lube it up and put it in a sealed bag.
http://www.amazon.com/Shomer-Tec-St...id=1375023727&sr=8-7&keywords=gun+storage+bag http://www.amazon.com/ZCORR-Anti-Co...id=1375020413&sr=8-3&keywords=gun+storage+bag
Bags of this type emit a chemical that prevents corrosion....protecting it for 20 years.
I like shooting my guns too much to store them too long...but I have stored some parts in bag that came with some of my new guns.....usually have a green tint to them...and labeled with a warning about disposal.
I would think that the vacuum bag trick would be good for a few years...but be careful what kind of desiccant you use...and don't let it come into direct contact with the firearm. Silicone dessicant packs are the only ones I trust...others can be corrosive....or gather moisture on its surface.
Just A good coating of gun oil will protect the metal for a long time.
Any subterranean storage...or "wet storage" area ....would require a VERY STURDY/WATERPROOF container purged with nitrogen or argon.