Falling home prices plus the foreclosure backlog probably mean a flat-to-down market over the next couple of years. But beyond the current desolation, three trends are aligning that figure to produce a major home-price boom over the next 20 years. One is economic: there could be a double-dip recession, but once the economy finally recovers, the factors that drive housing demand will follow. Second, most experts think prices are within 5% to 10% of a bottom. Pretty soon, prices will have been knocked all the way down — and as a general rule, the worse the crash in a market, the longer the subsequent recovery can last, because there is nowhere to go but up. The third, and arguably most compelling, reason is the near inevitability of inflation. In such an environment, any kind of tangible property appreciates rapidly. The boom we’re talking about will probably take more than a decade to unfold. But the next two or three years should offer exceptional opportunities for buying actual real estate — primary residences and vacation homes — preferably somewhere that’s green.