With today's inflation at 3%, will doubling my money in twenty years actually mean losing purchasing power? How do the one-year lockup and $10,000 yearly limit affect my need for flexible, inflation-beating options?

Given that the U.S. Treasury ensures that Series EE Savings Bonds will double in value after two decades, could these government-supported assets be emerging as the most reliable choice for conservative investors who prioritize stability over immediate returns?