OP here. We have an investment property already -- a condo in DC that I bought pre-bubble. It will be paid off in a few years and I'm considering buying another property when it is. DC real estate seems pretty stable to me, though, of course anything could happen. I would not rely solely on real estate income for retirement (we're saving elsewhere too), but I do like that rental properties, once paid off, can act sort of like pension fund, in that the won't run out of funds.