I'd love to have a wall mount, but I don't have that much wall space where I live at the moment. For the longest time I stored the rifle using a radiator as a rifle rack, but that obviously wasn't feasible when the heat got turned on. I wanted something secure and easy to latch when the rifle (AR-15 type) wasn't in a lockup.
Solution:
At the suggestion of my roommate, I went out and bought an "Auto Grab Guitar Wall Hanger" for about $15 dollars. It has a maximum load of 13~14 pounds and allows me to remove and replace the rifle easily and effectively with one hand on the pistol grip. Removal is accomplished with a firm upward and sideways pull. The stock is protected by padded foam surfaces, and the mount pivots a bit to allow the rifle to balance.
Pulled upwards:
Pulled out:
Replacing the rifle is just the above, in reverse. Obviously this won't work for every rifle... but for an AR-15 type it works wonderfully.
Video (iPhone does not love low light filming...):
Video (TinyPic Hosted)