Here's what I did during my Y2K paranoia phase:
First, you need mylar bags:
to fit in the plastic buckets (with O-ring sealed lids). Buckets alone won't maximize your storage life.
Mainly I got rice and beans, together they make a complete protein, are easy to prepare, and are dirt-cheap bought in bulk.
Put a bag in the bucket, take a 4 oz chunk of dry ice, wrapped it in a paper towel, put that in the bottom, then poured the stuff over it. Using an iron, seal the bag just leaving a corner open. As the dry ice turns to gas, it pushes out the air (CO2 is heavier then air). This kills any bugs or eggs in the food. After 15 minutes or so use the iron again to seal the corner, put the lid on, and it should last a couple decades at least.
All you need then is a source of clean water, and a means to boil it.