I thought about this too. I've stored a little bit for later use. Not enough to last me more than a year though. I think gas prices could spike back up any day now and you may lose your chance to get some cheaper gas.
A wise business-minded friend of mine recommended buying futures contracts for the amount of gas I plan on using for the next year or two. He said if I buy 1-3 year contracts at roughly today's price, if the price stays flat, I can sell them at current value and break even, but if it goes up, I could sell the contracts at the same proportion of increase in the price of gas I'm paying at the pump. Seems great in theory, but I haven't found the right market to trade on yet.
Also, if you know your local gas station owner, there's a chance you could negotiate something with him. Most stations have 10,000 gallon underground storage tanks, but in an effort to avoid having excessive inventory, they usually keep them pretty empty, receiving 1-3 deliveries a week of 1,300-2,800 gallons each fill up. If you could talk them into buying 500 gallons at todays price, have them store it, then you could keep an account with them for the volume you use. Now I think it's unlikely most store owners would do this, but you just might know that one that will go for it.